So here's Ladislausian soteriology in a nutshell.
The Sacrament of Baptism has two aspects to it: 1) the forgiveness and cleansing of sins and 2) entry into the Kingdom of God, the beatific vision as adopted sons of God into the family of the Holy Trinity.
#1 is effected by the graces of the Sacrament, but #2 is conferred in receiving the character of Baptism (the crown and the glory)
#1 deals with actual sin vs. actual virtue, the reward and punishment fitting each in justice, while #2 refers to unmerited grace that is owed to no one
#1 pertains to justification, and #2 to salvation. But BOTH #2 and #1 must be had for salvation, as someone with the character is lost if dying in a state of grave sin.
#1 is the NATURAL aspect and #2 the SUPERnatural
Recall how Our Lord taught that St. John the Baptist was the greatest of all born of women (in the natural respect, #1) but was less than the LEAST member of the Kingdom (note that word again). Ladislausianism also addresses the enigma of what Our Lord meant by that puzzling statement. Those born of women refers to nature, whereas those born again of God refers to super-nature. So as great as one could be naturally, that can't come close to the least bit of supernatural goodness.
So a martyred catechumen receives the Baptism of Blood, a perfect washing, and enters a state of justification and goes to Limbo, to enjoy perfect natural happiness for this act of perfect natural virtue.
But a martyred baptized person goes straight to heaven, since all their actual / natural sins are washed also.
Those who have the character but have some actual sin to cleanse go to Purgatory until they are cleansed so that they can enter the Kingdom.
Those who ardently desire Baptism and live virtuously will also have some (or even all) of their actual sin and punishment due to sin remitted as well (which seems to be what St. Ambrose is hoping for Valentinian).
So there IS in fact a baptism of desire and a baptism of blood, but these are only effective toward the cleansing or the washing part of Baptism, but not the glory or honor or crowning part ... which requires the character of Baptism and therefore the Sacrament.