This is not a "hate on Lae'zel" thread (for the record she's actually my favorite NPC), but it seems to me that the most likely outcome of going to a Gith creche is one of the following:
1) Lae'zel knows that she, and the entire party, will be killed pursuant to protocol, and the talk of a cure is false, intended to ensure compliance - the only reason I would doubt this possibility is that there are other ways to kill us and she's taking the risk of dying herself and not being able to ensure we bite the dust too (also her int and wis are high enough that she should know any plan that depends on her ability to deceive or persuade people is doomed from the start, or is lack of self awareness why cha is her dump stat?)
2) Lae'zel doesn't know because she's not senior enough yet, but while trainees are told to report to a creche for a cure, the actual protocol is to kill them under circumstances where you can be confident of success, and talk of a cure is false, intended to ensure compliance.
While I have no doubt that the Gith know more about ceremorphosis than anyone other than a mind-flayer, I do doubt they have enough access to recently infected hosts (ie before the point of no return) to have come up with a reliable cure, and given the nature of Gith culture I strongly suspect "life is cheap" is part of their philosophy and they have limited motivation to go out of their way to cure someone.
I personally suspect item 2 (I think it is more consistent with how the Gith knight acted, and also more plausible than Lae'zel's theory as to why things went down the way they did, and also more useful for the game when Lae'zel becomes playable as your MC) and is part of a story arc where in a later act she will, if her opinion of you is high enough, ultimately side with you in a conflict with her kin.
It's almost a shame that the NPCs will be playable "origin" characters. I like not being sure what their real agendas are, and I would actually have preferred that the scene with Raphael be animated such that it looks like you're alone in the room with him so you don't know what he said to the others or what their response was. That said, I will be very interested to see how the tutorial and content immediately after the crash plays out with different origin characters. If you're playing Lae'zel, do you meet someone else in the tutorial?