Regarding the last three, Vanya isn't particularly great on her own, and with that drug-addled dragon, I have absolutely no desire to acquire her.
A new Lesia would be a good addition to my water-based gun team, I think. It's good that she has a skill that works in the back row.
Rey has interesting mechanics; I haven't seen anything like it before, but I can't say yet how useful she is. As a character, I usually don't like harvesters, and in this case, I don't see anything that compensates for my dislike.