Rebecca - Ade ... is slightly disgusted. As a Pureblood with both a Mother and Sister who act like proper ladies of society, the idea of a woman burping as such through him through a loop. He doesn't know what to think of her. lol.
Leanne - As a healer I'm sure he's both sent a few people to see her and has seen her quite a few times himself. He's kind of terrified of St. Mungos and Healers make him VERY nervous, so I apologize for any snark/grief he will/has given her.
Olivia - She sounds adorable too!! All you people with adorable girls are driving Ade crazy. He has enough cute issues of his own. He has an aversion to things that are going to make him fat, so I don't see him coming into a bakery on a regular basis, but he'd probably lightly flirt with her and be friendly just to annoy Olivia's big sis ... not to say that Ade wouldn't like her. He'd probably think her love for helping out is amusing.
Carter - Awww. Unrequited love. Poor guy. As Ade's also a chaser and full of himself, I'm sure they get along well. Definitely friends.