i agree with Hack on the 40 Gallon breeder tank being the better option.
also what he said about cycling the tank. While clowns would probably survive a cycle in a 40 gallon tank it’s not the best way of cycling.
I for one like to seed a tank with with either live rock or San from a existing tank and then feed the tank with fish food or add a raw table shrimp. There are other ways using bottled bacteria like Dr Tim’s , and dosing ammonia.
as far as your stock list I also agree with Hack on the mandarin, nowadays you can get captive bred from a few breeder that eat frozen foods. I have no experience with them to say how they do long term on frozen. But providing enough live food can be a challenge.
