2. Do they have any annoying quirks? If so, what are they?
Lir is getting to see part of this in the RP with Sai and herself there. He will pick at skin when he is uncomfortable and will continue to do so until blood is drawn. Just a force of habit to keep his hands moving instead of staying in one place.
4. Any addictions? (Food, sex, drugs/alcohol, shopping, power/control, etc.)
Depends how you look at it. In Sara and Sai's life they have went through different bouts of time where they get addicted to different things quite quickly and easily. Sai has always fell pray to food and over eatingWhile Sara is faster to fall to drugs or sex among a few things that do a lot of self harm to their own bodies.
6. Their romantic relationships?
Mark their husband however they still do have their thoughts over Ava their old commander in the Talon Company who they are having a hell of a time trying to get over even now and after creating a family.