REQUESTS: A scavenger-partner that Zidane can drag with him; or, someone that Zid can shadow. Zidane isn't ecstatic about playing Follow The Leader, but there's safety in numbers!
A room mate, be it long or short-term, it's all good. If someone can tolerate his independency and competitive behaviour, snag a room! He'll give the best room to any woman who stays, because he can't stop himself. Skirt-chaser and all that, but he's only boastin'.
Random encounters: Zidane is generally friendly to most people; even if he's had a fight, physical or verbal or both, he's forgiving in most cases. There's enough shit happening in the world, everyone's got enough problems and don't need to add any more~
Canon-mates: There isn't a lot of characters that can be modified, and still be recognisable. Or those that can join, have limited canon. In short, Zidane is forever alone. He won't recognise any, non-FFIX characters; having said that, he'd click with other adventurer-type characters.