Ayla: She'd probably just grab your hand or peck you cheek to make her presence known to the other person, but if they go too far then she'd get really angry.
Finn: He'd most likely hide all his anger in, glaring at the person. He may loose his temper, but a lot of the time jealous Finn equals in a lot of snuggles and kisses.
Jack: Jack being..well Jack, I think he would come up to you and try to start making out with you. He wants the person to know that your his.
Malcolm: Malcolm I feel would be a tad bit shy and awkward about it, but he'd probably grab your hand and squeeze it to let you know that he's uncomfortable. Later he'd get overly affectionate.