Actually a lot of stuff is quite compatible as long as it doesn'tgo in there mouths - they're not especially aggressive. large clowns, dwarf angels,hawks are all good examples.... Shrimp, little clowns, damsels are the main ones to avoid. A dwarf lion will never catch a pseudochromis for example. Avoid maroon clowns tho' - they will beat on a dwarf lion real bad.
They are messy so I would only be looking at 2 or 3 fish total to go in there.