I don't know much about all but one of those fish, and that one is the violet (dragon) goby.
If you get a violet goby, you need a large tank, especially with all of those other fish in there. I'm sure you already knew this, but take into consideration that under good conditions one can grow to a foot long in its first year or so. You probably couldn't keep more than one, because when they hit about ten inches long, they seem to get very territorial. Also, from what I've read, eels and violet gobies don't mix. There have been accounts of the two living together peacefully for quite awhile, and then all of a sudden the eel kills the goby, for no apparent reason. I would imagine that a violet goby that starts to get territorial might see an eel as an intruder, and pick a fight with it. It wouldn't win, but it might start the fight.
Such a variety raises another question. Do they all require the same degree of brackish? I've read that scats need full marine as adults.
Hope this helps.