I have a Dwarf Lion and a Maroon Clown. I bought the Lion when he was very small. I have had him for about 6 months now, and he is 4 inches and pretty big around lol. He is doing excellent, and is a gentle gient. My Maroon Clown will even swim backwards into the Lion when it goes near his "fort", the Lion just swims back to his own fort. I have never seen the Lion go after any of my fish. Here are my fish listed in order they were introduced...
Maroon Clown
Decorated Goby
Atlantic Pygmy Angel
Fuzzy Dwarf Lionfish
Valentini Puffer
I think if you find a nice young Dwarf Lion, things will probably be ok.