Is this a good saltwater setup if not can you suggest something else?

Question

Fish: 2 reidi seahorse, 1 pearly jawfish, 1 blue sea star,1 Bangaii Cardinal, and 1 striped mandarinfish

Coral: Red Sea fan, sun coral, Clove Polyp, Toadstool Mushroom

Other inverts: Dwarf dusters, Purple Nudi, blue sponge, spiny sponge

All in a 55 gallon tank(note: I have none of these things yet)

Answer 1

Sounds good so far.  With seahorses, you will want to keep that tank fairly calm.  I don't know what you have in mind for lights, but I would recommend a T-5 lighting fixture.  You will need to have live rock in that tank unless you plan on breeding pods yourself.  Pods are the food source you will need for your mandarin fish.  It will most likely not take to other foods.  I wouldn't recommend a Nudi to beginners also.    

Answer 2

I think that sounds beautiful :)