Harley would love to have her cowboy on here, because I've loved him and Harley since seeing them in Assault on Arkham and my love for him grew since seeing the new film. Unfortunately she's not up for shipping with him, but she would love to have crazy adventures of the monster-hunting (and drinking) variety. If you decide to have him as an assassin, we have two on the site currently who would love to meet him, so there's plenty of plots available there. If you decide to have him reform and be good, he's welcome to either join the Guard or the Locke Detectives as a bodyguard or something. Alternatively he can just hang about and go on adventures with Harley all around Albion. There's probably also a high chance that someone or other would eventually take up Floyd's daughter for extra cuteness.
Because Harley's timeline isn't set in stone, I would love it if the Squad had actually done the movie mission beforehand and that that's how they met. All Joker scenes would have to be ignored because our current Joker is from the Nolan-verse, but I think it could be a lot of fun. I'm not fussed if you haven't seen the movie yet because it'll only be alluded to slightly, but I feel it would be great because all the members would be really close by then so their friendships in Albion would be solid. Most likely option of how he got to Albion is that a portal just swallowed him from his cell.
Faceclaim is Will Smith and I'd love you forever if you could keep him as that <3