Fr. Laisney in his book “Is Feeneyism Catholic?” states the following regarding Cantate Domino’s oft repeated ex cathedra pronouncement typically used in favor of Fr. Feeney’s interpretation of EENS:

(. . .)

Moreover, the  very  Council of Florence, in the very  same  decree for  the Jacobites (part  of the  bull  Cantate  Domino) mentions baptism  of desire!

SESSION 11 4 February 1442

[Bull of union with the Copts]

(. . .)

With regard to children, since the danger of death is often present and the only remedy available to them is the sacrament of baptism by which they are snatched away from the dominion of the devil and adopted as children of God, it admonishes that sacred baptism is not to be deferred for forty or eighty days or any other period of time in accordance with the usage of some people, but it should be conferred as soon as it conveniently can; and if there is imminent danger of death, the child should be baptized straightaway without any delay, even by a lay man or a woman in the form of the church, if there is no priest, as is contained more fully in the decree on the Armenians.

As we maintain that the observance of the holy Paschal time should in no way be relaxed, in the same way we desire that infants who, on account of their age, cannot yet speak, or those who, in any necessity, are in want of the water of holy baptism, be succoured with all possible speed, for fear that, if anyone who leaves this world should be deprived of the life of the Kingdom for having been refused the source of salvation which he desired, this may lead to the ruin of our souls. If anyone threatened with shipwreck, or the attack of enemies, or the uncertainties of a siege, or anyone put in a hopeless condition due to some bodily sickness, asks for what in his faith is his only help, let him receive at the very moment of his request the reward of the regeneration he begs for. Enough of the past mistakes! From now on, let all the priests observe the aforesaid rule if they do not want to be separated from the solid apostolic rock on which Christ has built His universal Church.

Where does it mention it?

That book is awful and very dishonest.

If you're claiming that because CD cites St. Fulgentius and St. Thomas that it endorses all their other thoughts on the subject, not only is that absurd, but

... ahem ... you are aware, right?, that St. Fulgentius explicitly rejected Baptism of Desire?

My OP request still stands. I want to know if this was addressed via a refutation by someone along the lines of Fr. Feeney or Fr. Wathen.

Where does it mention it? That book is awful and very dishonest.

As we maintain that the observance of the holy Paschal time should in no way be relaxed, in the same way we desire that infants who, on account of their age, cannot yet speak, or those who, in any necessity, are in want of the water of holy baptism, be succoured with all possible speed, for fear that, if anyone who leaves this world should be deprived of the life of the Kingdom for having been refused the source of salvation which he desired, this may lead to the ruin of our souls. If anyone threatened with shipwreck, or the attack of enemies, or the uncertainties of a siege, or anyone put in a hopeless condition due to some bodily sickness, asks for what in his faith is his only help, let him receive at the very moment of his request the reward of the regeneration he begs for. Enough of the past mistakes! From now on, let all the priests observe the aforesaid rule if they do not want to be separated from the solid apostolic rock on which Christ has built His universal Church.

If you're claiming that because CD cites St. Fulgentius and St. Thomas that it endorses all their other thoughts on the subject, not only is that absurd, but

... ahem ... you are aware, right?, that St. Fulgentius explicitly rejected Baptism of Desire?

You (and Laiseney) left out the part where St. Fulgentius rejects Baptism of Desire.  By Laisney's own (dishonest) argument, this "proves" that Florence rejected Baptism of Desire.  

Sorry, but that's one of the dumbest things I've ever heard, that a citation from a Council of some passage from a saint means that the Council is teaching everything the cited author teaches about the subject

I’m also not particularly impressed with your objection.

If you’re interested in bickering or arguing then please do it elsewhere. I simply want a source regarding my concern.

I didn’t leave out anything because I am not the one making the argument in the first place. I’m also not particularly impressed with your objection.

If you’re interested in bickering or arguing then please do it elsewhere. I simply want a source regarding my concern.

My OP request still stands. I want to know if this was addressed via a refutation by someone along the lines of Fr. Feeney or Fr. Wathen.

Infant Baptism: It's Necessity

That this law extends not only to adults but also to infants and children, and that the Church has received this from Apostolic tradition, is confirmed by the unanimous teaching and authority of the Fathers.

Besides, it is not to be supposed that Christ the Lord would have withheld the Sacrament and grace of Baptism from children, of whom He said: Suffer the little children, and forbid them not to come to me; for the kingdom of heaven is for such; ° whom also He embraced, upon whom He imposed hands, to whom He gave His blessing.

Moreover, when we read that an entire family was baptised by Paul, it is sufficiently obvious that the children of the family must also have been cleansed in the saving font.

Circuмcision, too, which was a figure of Baptism, affords strong argument in proof of this practice. That children were circuмcised on the eighth day is universally known. If then circuмcision, made by hand, in despoiling of the body of the flesh, was profitable to children, it is clear that Baptism, which is the circuмcision of Christ, not made by hand, is also profitable to them.

Finally, as the Apostle teaches, if by one man's offence death reigned through one, much more they who receive abundance of grace, and of the gift, and of justice, shall reign in life through one, Jesus Christ. If, then, through the transgression of Adam, children inherit original sin, with still stronger reason can they attain through Christ our Lord grace and justice that they may reign in life. This, however, cannot be effected otherwise than by Baptism.

Pastors, therefore, should inculcate the absolute necessity of administering Baptism to infants, and of gradually forming their tender minds to piety by education in the Christian religion. For according to these admirable words of the wise man: A young man according to his way, even when he is old, he will not depart from it.

Infants Receive The Graces Of Baptism

It may not be doubted that in Baptism infants receive the mysterious gifts of faith. Not that they believe with the assent of the mind, but they are established in the faith of their parents, if the parents profess the true faith; if not--to use the words of St. Augustine--then in that of the universal society of the saints; for they are rightly said to be presented for Baptism by all those to whom their initiation in that sacred rite is a source of joy, and by whose charity they are united to the communion of the Holy Ghost.

Baptism Of Infants Should Not Be Delayed

The faithful are earnestly to be exhorted to take care that their children be brought to the church, as soon as it can be done with safety, to receive solemn Baptism. Since infant children have no other means of salvation except Baptism, we may easily understand how grievously those persons sin who permit them to remain without the grace of the Sacrament longer than necessity may require, particularly at an age so tender as to be exposed to numberless dangers of death.

Baptism Of Adults

With regard to those of adult age who enjoy the perfect use of reason, persons, namely, born of infidel parents, the practice of the primitive Church points out that a different manner of proceeding should be followed. To them the Christian faith is to be proposed; and they are earnestly to be exhorted, persuaded and invited to embrace it.

They Should Not Delay Their Baptism Unduly

If converted to the Lord God, they are then to be admonished not to defer the Sacrament of Baptism beyond the time prescribed by the Church. For since it is written, delay not to be converted to the Lord, and defer it not from day to day, they are to be taught that in their regard perfect conversion consists in regeneration by Baptism. Besides, the longer they defer Baptism, the longer are they deprived of the use and graces of the other Sacraments, by which the Christian religion is practised, since the other Sacraments are accessible through Baptism only.

They are also deprived of the abundant fruits of Baptism, the waters of which not only wash away all the stains and defilements of past sins, but also enrich us with divine grace which enables us to avoid sin for the future and preserve righteousness and innocence, which constitute the sum of a Christian life, as all can easily understand.

Ordinarily They Are Not Baptised At Once

On adults, however, the Church has not been accustomed to confer the Sacrament of Baptism at once, but has ordained that it be deferred for a certain time. The delay is not attended with the same danger as in the case of infants, which we have already mentioned; should any unforeseen accident make it impossible for adults to be washed in the salutary waters, their intention and determination to receive Baptism and their repentance for past sins, will avail them to grace and righteousness.

Nay, this delay seems to be attended with some advantages. And first, since the Church must take particular care that none approach this Sacrament through hypocrisy and dissimulation, the intentions of such as seek Baptism, are better examined and ascertained. Hence it is that we read in the decrees of ancient Councils that Jєωιѕн converts to the Catholic faith, before admission to Baptism, should spend some months in the ranks of the catechumens.

Furthermore, the candidate for Baptism is thus better instructed in the doctrine of the faith which he is to profess, and in the practices of the Christian life. Finally, when Baptism is administered to adults with solemn ceremonies on the appointed days of Easter and Pentecost only greater religious reverence is shown to the Sacrament.

In Case Of Necessity Adults May Be: Baptised At Once

Sometimes, however, when there exists a just and necessary cause, as in the case of imminent danger of death, Baptism is not to be deferred, particularly if the person to be baptised is well instructed in the mysteries of faith. This we find to have been done by Philip, and by the Prince of the Apostles, when without any delay, the one baptised the eunuch of Queen Candace; the other, Cornelius, as soon as they expressed a wish to embrace the faith.

http://www.catholicapologetics.info/thechurch/catechism/Holy7Sacraments-Baptism.shtml