Stubborn,
You speak of possibilities whereas Trent speaks of what "sometimes happens." And once again, Ex Omnibus Afflictionibus teaches that catechumens can be justified by perfect charity before their baptism (but with the necessary intention of receiving it, cf. nn. 31, 33: see the CE article, Baptism for confirmation of this interpretation).* You say that it cannot happen unless one is baptized, as though someone killed on the way to Church to be baptized would be stripped of his justification.
Trent teaches the sacrament is necessary unto salvation - which you agreed Trent taught this.
Trent teaches that sometimes justification is possible before the actual reception of the sacrament - but Trent does not mention anywhere what happens to the theoretical catechumen who dies justified but without the sacrament.
All we really know with certainty, is that the theoretical person did not receive the sacrament therefore does not go to heaven - we know this for certain because Trent taught the sacraments are necessary unto salvation and the catechumen did not receive the sacrament.
All speculation regarding the departed catechumen's whereabouts can only be just that - speculation - but one thing is for certain, without the sacrament there can be no salvation according to Trent.
* Pre-Trent, we find the teachings of Popes Innocent II and III (Denz. 388, 413). And right after Trent, its Catechism teaches BoD. How could the very same Fathers misinterpret a solemn teaching from only two years prior (Trent closed in 1564, the RC was promulgated in '66)?
Here is Trent's catechism, please find and post where it teaches a BOD.
In fact, I already will tell you that there is no teaching about a BOD in Trent's catechism for the simple reason that Trent never taught it. In the quote below Trent's catechism explain what the infamous words; "or the desire thereof" mean.
Below the quote, you can see the progression of error being taught through the catechisms as Trent's teaching transforms from one must not only receive the sacrament, one must also desire to receive it - into salvation via some desire without the sacrament.
Dispositions for baptism
Intention
The faithful are also to be instructed in the necessary dispositions for Baptism. In the first place they must desire and intend to receive it; for as in Baptism we all die to sin and resolve to live a new life, it is fit that it be administered to those only who receive it of their own free will and accord; it is to be forced upon none. Hence we learn from holy tradition that it has been the invariable practice to administer Baptism to no individual without previously asking him if he be willing to receive it. This disposition even infants are presumed to have, since the will of the Church, which promises for them, cannot be mistaken.
Catechism of St Pius X (1908):
17 Q. Can the absence of Baptism be supplied in any other way?
A. The absence of Baptism can be supplied by martyrdom, which is called Baptism of Blood, or by an act of perfect love of God, or of contrition, along with the desire, at least implicit, of Baptism, and this is called Baptism of Desire.
Baltimore Catechism (19th and 20th centuries):
159. Q. What is Baptism of desire?
A. Baptism of desire is an ardent wish to receive Baptism, and to do all that God has ordained for out salvation.
"Ardent wish" by one who has no opportunity of being baptized-for no one can baptize himself. He must be sorry for his sins and have the desire of receiving the Baptism of water as soon as he can; just as a person in mortal sin and without a priest to absolve him may, when in danger of death, save his soul from Hell by an act of perfect contrition and the firm resolution of going to confession as soon as possible.
Q. 653. Is Baptism of desire or of blood sufficient to produce the effects of Baptism of water? A. Baptism of desire or of blood is sufficient to produce the effects of the Baptism of water, if it is impossible to receive the Baptism of water.
Myrna'M's book on a BOD
An adult who for some reason or other cannot be baptized, can never the less, by an act of perfect love of God or perfect contrition, gain sanctifying grace and save his soul.
CCC
1259 For catechumens who die before their Baptism, their explicit desire to receive it, together with repentance for their sins, and charity, assures them the salvation that they were not able to receive through the sacrament.