TK,
The two important texte concerning the ordain/reordain question is first, of course, the Vinaya, then second, I think, Gendun Drup's (1st DL) commentary on vinaya. I think this is the text we rely upon in the Gelugpa tradition for such matters.
I think you are right in saying the is a distinction wether or not the leaving of the vows was done in a concealed manner ("defeat") or not. You are also right I think in saying that there is probably a possibility for reordaining, but that it is generally not in our "gelug culture", as you call it.
In any case, it's really up to them to decide how they want to work for the benefits of sentient beings...but even the possibility of him (Trijang R.) eventually reordaining give a little solace