All in honesty, i would make some changes to your stocking..the tangs along with the 6 damsels do not make a peacefull environment..And, as stated above, the only tang you could get away with is the yellow tang, and even then, your borderline..If it was me, i would at least take back the palani tang and stick to the yellow untill you already have a larger tank in place...
Buying fish, and then "planning" an upgrade in the future is not ideal, as we all know, things happen, things change and that lovely aquarium that we were planning never materializes...Sorry, but just being realistic here..
You could do a Foxface Rabbitfish, they have great character and the added "cool" factor of venomous spines. The bluechin trigger would also work in a 75g. Both have the added benefit of being reef-safe too.
If you're just FOWLR, I'd 2nd the dwarf angels, they're beautiful. There are a bunch of pretty wrasses out there. Could do a royal gramma. Lots of folks like the combination of pistol shrimp/goby