to be honest. a 75 makes a great reef tank. When i think of a fowlr i think of triggers, large angels, eels, lions, and groupers. For the most part none of those will fit in a 75 for life.
I guess fish you could make work would be:
1. dwarf angel
2. hawkfish
3. toby
4. dottyback
5. damsels
6. filefish
7. dwarf eels
8. a small tang(kole, tomini, yellow)
9. clownfish