Correct Chromis are a member of the damsel family, but unlike other damsels are relatively peaceful. I have a school of 5, but with your current load I would not get more than 3. Is getting rid of the yellow tail an option? It may be aggressive toward chromis or other smaller fish.
Otherwise I think the damsel might be a problem for anything other than a yellow tang anf I would wait on a yelow tang if that is what you want.
Tank: 90 Gal SW Reef in the making
See my info for setup and inhabitant details: