You could keep some shrooms, maybe some leathers. Nothing that requires high lighting. You have a FOWLR light for sure. You could potentially keep any non-photo coral, but if you plan on FOWLR, you are most likely not going to have the most pristine water quality (i.e., nitrates, phosphates, etc.). If you are, you might as well go reef if you're making the effort, and if that's the case, better lighting.
I'm a believer in the One or the Other, not Both aquarium. Either do corals, or don't, don't try and make a tank that could kinda do both, cause it's not worth it. JMO