Witches share a symbiotic existence in that their magics naturally compliment each other and helps to fill the weaknesses of the other. While there is certain to be some airs put on by some families, for the most part they're able to get along. That said, depending on how Duncan treats him would very much dictate how Aran responds to him. If Duncan treats him well, Aran would do likewise. As a masseuse his services could be used in that matter. Especially when you pair them with his magic.
As for Bethanie... LOL. Oh gosh, never call her 'Beth'. There would be glares and ignoring. She hates that. He can feel free to come through her bar, that's fine. She's anti-slavery, but owns a slave... because she didn't want Maya ending up somewhere bad. So there is that.
With Bishop, that is definitely an option. Bishop is kinky as hell, so he's typically a good sport for exploring. He likes to have fun, though he is super careful and wont bring shame to Patrick's household, nor inconvenience his master.
It will definitely be interesting to see how things develop. But I can definitely tell you, if Duncan takes on Shay's case? there will be no in-road with him. Desi doesn't appreciate people messing around in his life uninvited. So beware. Desi isn't one you wanna trifle with easily.
As for Marek, well, there is actually quite a lot of potential. He is not in the law sector himself, however his entire family is. His father is the ADA, his grandfather is a judge, his oldest brother is a lawyer, and his middle brother is a cop. His family for generations has heavily influenced the law enforcement of Sol Nocte. So there is the potential for connections and possible meetings, or of at least knowing of each other. Marek may be pursuing music right now, but he's still his parent's son.