VQuintessence
5 works - if you have too many, its feels like you're playing pokemon and its hard to build up characters properly. 1. Catwoman 2. Poison Ivy 3. Power Girl (Karen Starr - She is far more mature and understanding of the cruelty of the world - plus super attractive) 4. Raven (I believe you already decided on her?) 5. Hard to day tbh, I can see Harley being an option but even the powerful yet warrior Wonderwoman could as well?
I do like Zatanna, but Raven is an absolute must. I thought you were nuts for wanting Harley in the beginning but then I read how Ian was absolutely bonkers, so they make a good fit haha. I also don’t think it’s a bad thing for there to be a little conflict between harem members and Ian, this does not mean I want Ian to change at all but maybe grow a bit in character and learn to appreciate the feelings of his women? They also don’t have to like his criminal activities or even tolerate it too much for it to work well, just have them appreciate each other for who they are other than just what they do, I think you could pull it off. But yes basically you must add Raven. She is just too awesome.
as long as you don't drastically change the personality of said characters just you could add the harem it should be fine. like harely quin , poison ivy and black cat already work but adding random like wonder woman, star/black fire, super girl, raven and stuff won't work as they have drastically different personality and habits than the other girls and Ian; this may cause confusion and conflict, or just characters that look like i.e. wonder woman but act like nothing like them. also some characters like raven range from a teen to at most a very young adult and it just rubs off the wrong way.