First piece of advice? drop the -s of the tangs.
If you research more, read more, etc, you'll learn that they are prone to a lot of disease and need a lot of swimming room. Best to keep one in this size tank, to avoid a lot of headaches. This is MO, but you definitely will not be keeping multiple blue tangs, as two similar tangs will not get along.
Catalina gobies are a colder water species, and do not tend to do well long term in our tanks, unless they are species specific tanks (where the temp, etc, is set up for a particular species).
Chromis do best in small groups, and you may or may not wish to take up limited 'space' with them. You will not stock a saltwater tank anywhere near that of a freshwater tank (esp if you are used to cichlids...in SW the rough rule is 1" of fish per 5 g, not 1" per g....and this is modified based on the fish and whether you have corals or not). It also takes much longer to establish and stock a saltwater tank. Much longer.
You will need a heater (prefer two) and additional power heads for circulation. Forget air pumps and stones, which are not used in salt water tanks. A protein skimmer would be really good, but not absolutely necessary- at least not right away. But you may wish to reconsider the Fluval (especially if it will cost a lot) which, though good for running carbon, is not the best choice for a saltwater tank (though many use them). A refugium might be a better choice. A refugium is a separate tank/box under the stand (typically), where there is a bunch of sand, some algae, and little bugs. This helps greatly in biological filtration. Many people will use live rock, a deep sand bed (DSB) and a refugium as their filtration...and may or may not use a protein skimmer.
A fine sand is better than crushed coral, and live rock is really more appropriate than artificial corals and the like. Live rock (though base rock is often used as the 'brick' behind a facing of the more expensive live rock, which will colonize the rock underneath) is a natural structure, and will help keep many types of fish which graze on it.
Lighting is a major issue for keeping corals and anemones (which are often not kept together). It is a separate issue entirely, and you may wish to post new threads based on your planning as you progress in your learning curve.
I would definitely get a good book or two.
Do some searches for:
DSB (deep sand bed)
refugium
live rock
live sand
I think it will help to do some searching for what sort of tank you might want to keep, before people can really give you too much advice on what else you can put in it.