i'm having a hard time believing what you claim to have seen was legit. sorry. if it was i'll eat my words, but ... yeah. no offence or anything! :S
also, just throwing in my two cents: to me, chris/jill to me are one of those "are they or aren't they" things like mal and inara, moulder and skully, bones and book, etc....i think there are enough little moments and subtext to keep fans of the pairing ( like me!
) on the edge of their seat with excitement, but not enough to confirm so it always keeps people guessing. i know all those pairings (with the exception of mal and inara) actually happened, but video games a bit of a different breed. i don't think they'll give chris and jill their "happy ending" until they are completely done with the characters (at least as playable) - if they even do at all. i get the feeling if they ever made chris and jill get together on screen while still actually continuing their story, they would eff something up and people would complain. especially people who aren't fans of the pairing.
anyway, i don't really expect anything.
as for leon and ada, it's not that i don't like the idea of them together - i'd just be surprised if it actually happened again. ada is super flakey and leon seems like quite the playboy himself. we'll see though!
as a heads up, if you're taking IMDB's word for ada being confirmed in the game, be aware that it could be false. IMDB can be edited by anyone. i remember there was one time when aunt may was listed as carnage for one of the spider man films.... lol