i need some suggestions

Hi i have a 75g with a 20g sump no protein skimmer also run a aquaclear70 in the sump for chemical filtration
Fish:
Tomato clownfish
Powder brown tang
Bursa trigger
Fire fish
Green mandarin dragonet
2 3 striped damsels
Six line wrasse
Cleaner shrimp
3 unknown crabs

Ive had the tank for almost three months any helpful suggestions and i want to add a coral beauty a flame angel a koran angel and maybe a school of 4 or 5 fish any suggestions