R 1: No, Linhardt's never been in love. He loves people, he's had sex, and he's attracted to people/has felt the beginnings of romantic love but never been full head over heels. R2: Pansexual and very open about it. Gender and species don't mean anything. New is good.
F10: Depends on the situation. He'd probably do anything Caspar needed him to do. For anyone else, there are limits and things that he's going to outright refuse. He's more flexible on personal grounds than ideological ones - more likely to help someone cheat or get away with something he doesn't approve of than to hurt someone.
R10: Honestly, yes and yes. Linhardt's a great flirt, he loves banter and being inappropriate, he's confident, and he's good at wordplay. He just doesn't initiate often because he's not good at telling when a situation calls for flirting.
F6: He is, but not in an obviously affectionate way. He's more the type to exasperatedly fix his friends' clothes, or touch them when teasing them about something (elbow on Cas's head for being short, etc.) than open affection when it comes to physical contact.
R9: Not really? He's never been in love. He does assume that all his crushes are unreciprocated, though. He just pretends it doesn't bother him to be too weird for love.
F4: Linhardt likes people who are unashamed about being who they are, people who are interesting/share an interest with him, and people with a strong moral compass. (Note: Said compass does NOT have to agree with his.)
friendship: 10