BOD was taught at Trent, Session VI, Chapter 4, and so infallible in that regard as "agree[ing] with past dogmatic statement[]." So much for the Catechism not being infallible on that point.

That's the thing, though; there's no evidence that the passage in the Catechism was attempting to interpret Trent or whether it was just a general treatment on the subject.  So you can't even read that as some official interpretation of Trent.  If the passage in the Catechism does refer to BoD, however -- and there's room for doubt IMO as I've seen the Latin -- then it's obvious that the authors of the Catechism did not see BoD as incompatible with the teaching of Trent.  But that's really as far as we can take it.

It didn't cite Trent so you can say there is no direct evidence. That's fine.

St. Robert cited Trent Session VI, Chapter 4 as supporting BOD. Of course, he could be wrong. He is, however, support for that view. I tend to agree with him - that's all.

There is room for discussion among Catholics in good faith, and you are an example of that, as I hope I may be.

Even if you think that Trent VI.4 is referring to BoD, the statement there falls about as far short of a definition as you can get.  Trent never teaches that Desire ALONE can suffice for justification ... just that it cannot happen without it.  Trent teaches that Desire is a necessary cause but falls short of declaring it a sufficient cause ... due to the "cannot happen without" language.  Trent does not positively teach that justification (and then salvation) CAN happen WITH DESIRE ALONE ... as Trent does for Confession.  Not to mention, Trent makes NO mention of how it works and the conditions necessary for it to work.  Consequently, I've probably heard half a dozen different explanation of the requirements for BoD.  That's prima facie evidence that the Church has never defined it.  Really the greatest common denominator among BoDers is this notion that Baptism is not necessary for salvation.

I read Trent as teaching that BOTH BAPTISM AND THE DESIRE are necessary for justification.  Why?  Because of the passage immediately after it, the citation from Scripture which says that one cannot be born again without water AND the Holy Spirit.  Trent was making an analogy between laver:Sacrament::desire:Holy Ghost (if you know analogy punctuation -- if not I'll explain it).  So Trent is supposed to be saying, "One cannot be justified without either Baptism or else the desire for it because Jesus taught that water (Baptism) AND the Holy Spirit (desire) are necessary for being born again?  That doesn't make sense to me.  I used to believe in BoD for Catechumens ... because I thought it was in Trent ... but then I sat down and read the entire Treatise on Justification in Latin, and it jumped out at me that Trent was teaching no such thing.

Language is similar to this:  "You can't play baseball without a bat or a ball."  This is ambiguous on its own.  It could mean that you can play if you have one or the other (BoDer interpretation of Trent) or else that you can't play with either one missing (my reading of it).  But when Trent follows this up with citing as Scriptural proof "water AND the Holy Ghost" ... that immediately disambiguates it in favor of how I read it.