Welcome to AA!
Being a fellow 55 gal
owner, I can tell you that the fish your looking at is going to be too much for it. You could probably get away with one of those and be okay, but not all of them. Also most of those fish will outgrow your tank quickly, the exception being the lion fish. What I recommend is that you use the 55 gal
to learn the ins and outs of the SW
game and then maybe look to get a bigger tank going in the future for your aggressive tank. A 125 gal
tank filled with killers is a cool thing to see.
As far as the filters, if you get around 60-75lbs of live rock in there you can ditch the HOB
filters completely. As the others have said, you can go with 20-30 lbs live rock and get the rest as base rock to cut cost. The rock provides almost all of your filtration and what it doesn't do, the skimmer will get for you.
I agree with the others about the C.C. it is a royal pain in the rear that I am currently fighting with in my brothers tank and we are going to be getting rid of it over the next month. Sand is much easier to maintain because you can get critters in there that do the work for you.