The blue hippo tang will get too large for a 55, but the yellow tang will be ok. These are also of different genius, so if you ever do upgrade to a larger tank you could still get the blue hippo. The blue hippo isn't a good fish for a beginner, their skin if very prone to ick and other diseases like line erosion. Also, I would avoid the volitan, he will also get too large. A good substitute thier is the dwarf lionfish, which only get half the size of the volitan, which means they will have a much smaller mouth and you would then be able to get even perculas if you would like. I wouldn't suggest the goby though, they tend to stay around the bottom where your eel would be.
My suggestion:
1 Yellow tang
1 Dwarf lionfish
1 Dwarf angel(flame my fav.)
1-2 Black & White percs(my fav. for clowns)
1 Snowflake eel
1 Lyretail anthia(highly underrated fish)
This many fish and eel, make sure you have more than enough filtration and LR, possibly 2 canisters and protein skimmer. I could point you in the direction of some cheap, but quality canisters.