Need advice on buying a fish

I agree, get a wrasse (I personally LOVE the Hawaiian or second choice is the McCosker). Your Naso is going to get quite large, so no other tang...

 

The Potters angel like all dwarf angels are reef safe 'with caution",simply means may or may not nip at corals or clam mantles.I've had one in my tank with soft corals,LPS corals and a maxima clam for about a year and a half with no problems.Others have had success with them as well as some of the other dwarf angels,but theres always an equal chance of it not going well.It's just a question of whether or not you like these fish enough to take a chance on them.The Kole tang should be fine with your naso,the Blue Hippo I'm not too sure about,also could need a larger tank.