Hum, I think you've got a lot of choices! I'll recommend what I have since these are what caught my eye...
I have a green finger leather which I really like (not sure what color yours is). I also keep a yellow leather and toadstool, both pretty cool. Mushrooms & ricordia are nice too (ricordia is one of my new addictions, some are just spectacular, those ones are also quite spendy). I used to have a saddleback leather that got just huge. My clowns hosted in it, until I got them a real anenome. They switched homes and the saddleback perished within a week after that. I've also heard stories about clowns hosting in toadstools. Maybe it would be cool to get something your clowns will take to...probably any softy with nice long polyps.
I don't think any of the softies will be a problem with the fish you have. But you may want to make sure there's some space between the corals themselves, as they can release toxins in the battle for space with each other. Along those lines, good filtration and possibly some carbon use may be good ideas when combining different softies.
hth,
Rob