Stocking plan for new 55g

I agree with Vinny to use more caution because of the unpredictability. My green spotted puffer has never bothered any of my crabs or snails but that doesn't mean I'd ever recommend trying one if you care about having inverts because it would be very hard to find another with that behavior. There are a lot of angels that usually are a problem too and should be avoided if you care about having coral, etc.

I'd also avoid a mandarin with a sump that small for pods to breed in safely, and I would avoid chromis because you already have the clowns which are in the same family. I'd look into something like a royal gramma to add some color to your fish list, or maybe a midas blenny.