How is Christina's quest meant to start...? I mean for when you can pick how to handle her? I can't do anything with Lariska until then. If I talk to her she just tells me off and she rarely decides to pick on me in random scenes.
You just gotta get enough of those random events, and consistently pick your reactions. Either stay quiet or stand up to her, don't do one at one event and another at different.
Once you've done that enough (5-6 times maybe?), quest log updates and then you go talk to her during a break and decide to either fight, submit or blackmail.
Blackmail is easiest and best. You just spot her after class the next day or something like that, and then you go blackmail her on the next break.
Oh... And um are the Rex parties meant to continue in the current version? I went to the second one, but I can't seem to get it to repeat...
I think they can get bugged if you skip a few, but basically you gotta get Anya to invite you to one, and then they happen every other Friday, IIRC, but don't talk to Anya monday-thursday and get yourself invited to the party, because that messes it up. Best to just show up outside the community center 16.00-18.00 and talk to Anya.