Shiro
Easiest way to get on his good side: Treat him like a normal person! Offer to help in the war. Don't be impressed by Othello's charms. And it helps if you're not easily squicked out by gore.
Easiest way to get on his bad side: Killing him! He hates that. Threatening Kuro, Lika, anyone like that. Badmouthing Ororon. For that matter, talking shit about Othello. That's his job. Taking a joke too far. And for the love of god, don't point out the ears. He knows.
Favorite person: Kuro. But Lika is damn close. So's Othello, but shh.
Favorite person met on the comm: Tifa. Kadaj is in his bad books at the moment.
Prefers: Bossy people. No, I don't know either. And he's straight. Completely. Honest. Don't listen to Othello. Ever.
Schrödinger
Easiest way to get on his good side: Be interesting, be intelligent, be powerful! He likes being seen as a valuable commodity. Above all, be fun to play with.
Easiest way to get on his bad side: It's not easy. He treats everyone like toys, so even if you get mad at him, he'll just laugh. However, if you somehow manage to trap him somewhere? He'll make you regret it.
Favorite person: The Captain.
Favorite person met on the comm: B. He's just so much fun.
Prefers: People with a sense of humour. Who cares about gender?
Tseng
Easiest way to get on his good side: Have an enthusiasm for your work, be diligent. Respect him, and respect the Company, and respect Rufus, most of all. Be kind and sweet.
Easiest way to get on his bad side: Threaten or insult Elena. Threaten ShinRa. Be lazy, crass, stupid.
Favorite person: Elena.
Favorite person met on the comm: ...he really doesn't interact much.
Prefers: Girls that let him be overprotective.
JENOVA
Easiest way to get on her good side: Give her the utmost respect. Treat her like a far superior being, something to be treasured. Show some willingness to indulge her odd motherly instincts.
Easiest way to get on her bad side: Take one of her children from her, pollute her gene pool, insult her.
Favorite person: Rufus. Her children.
Favorite person met on the comm: She was quite fond of Sakura.
Prefers: ...her children.
Scarlet
Easiest way to get on her good side: Tell her she's beautiful, be intelligent, like weapons, be somewhat amoral.
Easiest way to get on her bad side: Threaten her or the Company, insult her appearance or her skill at designing and using weapons. People with a justice complex can go swing too.
Favorite person: Rufus.
Favorite person met on the comm: Ash, probably.
Prefers: Men with class.
Bridget
Easiest way to get on his good side: Take him seriously. Acknowledge that he's male. Have a strong sense of justice!
Easiest way to get on his bad side: Insist he's female, or otherwise make fun of his appearance. Hurt the people he cares about.
Favorite person: Does Roger count as a person? If not, probably his brother.
Favorite person met on the comm: Larsa!
Prefers: Beautiful, strong people. He's not fussy about gender, or rather he doesn't know any better.
Maru & Moro
Easiest way to get on their good side: Be funny! Do silly things, entertain them, come and visit them!
Easiest way to get on their bad side: Hurt the Mistress, or insult her. Make fun of the fact they can't leave the shop.
Favorite person: The Mistress!
Favorite person met on the comm: Youji and Natsuo.
Prefer: ...each other, I suspect.