Marine Invertebrates

first of all i have to say that is WAY too many fish for a 75. i'd cut your number down to closer to around 10 especially if you are set on that tang who will have a big 'ol bio-load. really the tang is cutting it close on size for a 75g... also mixing angels is never recommended so if you start cutting fish off the list i'd start with one of them.
your snails most likely won't reproduce so don't worry about that. you can feel free to mix varieties. as far as shrimp goes, skunk cleaners are my favorites. they tend to hang out together a lot. you can have 3 in your 75g. stay away from coral bandeds if you want other shrimp in the tank. fire shrimp are a little more shy but are quite beautiful.
#1 rule with SW - go slow! if you do this, don't plan on getting anything in your tank after filling it for like 6-8 weeks! and after that you only can get like 1-2 fish a week. it takes a while to get going but it sure is worth it. just don't think it's like FW cause it's not!

i agree with Salty stay away from coral bandeds.even though they do look good.

Here are some specific suggestions that I have based on my experience and what I've heard:

1.) You can not keep two dwarf angels together in your tank unless you have a huge tank. Some people have luck with keeping 2 dwarf angels but its really rare. I think the flame angel is a very nice looking fish so I'd definitely get one of those.

2.) I would stay away from damsels. Most damsels are territorial and can be real terrors in the tank. I had some chromis in my tank who are relatively nicer damsels and they picked on my clownfish to death. The yellowtails might be one of the less aggressive ones but as a general rule damsels aren't something I recommend to most aquarists.

3.) I think the clowns are good suggestions. You have a number of varieties to choose from that should do well. I have pink skunk clows instead of the typical "nemo fish" that everybody else has.

As a general rule, I would consider each fish that you add as one less fish that you can add later. While there are some people who can swap fish in and out of their tank at while, I've never had much luck doing that. I would think very carefully what you add.

I'd also say that I'm not sure these stocking lists are really a great idea. I would prefer to apply what I would call a "stocking concept" or "tank vision". In that, you apply this process:

1.) Decide what the overall tank will be like. Will you have a number of smaller fish or 1-2 large fish. I think you've already done that.

2.) I would decide on a centerpiece fish which is your largest fish. The yellow tang is a good one for a 75 gallon.

3.) After that, I would start finding complementary fish. For example, you'll probably want a fish to keep the sand stirred up. I have a Rainsford Goby.

4.) You'll probably want a mixture of fish that swim and fish that hang out in the rocks. The clownfish could be your swimming fish. A goby or blenny could be one that fits in that category.

One reason to avoid a strict stocking list is that it takes away the fun of going to the fish store and seeing a really cool fish. I never really liked hawkfish until I saw them in the store and now I think they are great. Unfortunately, the last 3 I have had have jumped out of the tank so I don't think I'm getting any more.

Just be patient, don't rush, and enjoy the process of looking at fish. You won't be ready to add fish anytime soon.

shy away from damsels. and i have heard flame angels have a low sucess chance...

Flame angels actually do fairly well. They are a moderately hardy angelfish, IME.

Indeed. Flame Angels have been relatively hardy in the experience I have with them.

Way too many fish IMO. Disregard the fish to gallon ratio and play more attention to their bio-load. Is this going to be a FOWLR or a Reef set-up? what are you planning on using as your filtration?
As others have mentioned I would ditch the damsels and a dwarf angel. would also ditch the threadfin and some of the gobies. Personally I would chop the stocking list to this:

Yellow Tang
Flame Angel - Known to nip at corals if you're planning on a reef set-up
Pair of Clowns
Pair of Fire Gobies
A watchman goby

As far as inverts. I would do Cleaner Shrimp as salty mentioned, they hang out together and aren't as shy as Fire shrimp. 4 should be a good number. Snails do reproduce in tanks but you won't see many of the babies make it into adulthood, they're pretty much fish food. I would do a mixture of snails" Turbo, Astrea, Cerith and Nassaurius. for hermit crabs I would do Dwarf Blue Leg Hermit Crab and Scarlet Reef Hermit Crab.