A flame angel in a fish-only 75g would work. Reef would probably be okay depending on what you had, but its no guarantee that they would nit nip at some corals.
The Yellow Tang really should be in larger than a 75. Six foot long is good. There are some nice tangs that would work in a 75, but the list is fairly limited. People will argue and debate the six foot concept, but it just seems to work. You rarely see people with Tang problems when they are in the suggested tank size.
Check out sites like liveaquaria.com for tank size recommendations, fish computability, etc.