Here's my thoughts...
Question #1 :
That looks like a red/orange tree sponge (which always seem to die in home aquaria) and if it is a sponge and was exposed to air, it will die much quicker, just kinda melts away..
#2: The finger leather is nice, it should do fine from the bottom level in the tank to mid/high depending on what you have for lighting, medium flow is fine for that coral.
#3: for your star polyps, you can most defiently take the hanging piece off and rubberband it or superglue the underside to another rock, it will take fairly quick with either method
#4: Zoa's are the real name or Palyzoas, Palys are the larger of the zoo's, polyps are pretty much the same as zoo's zoa's, Everyone calls them something different, I'm no expert on this one but it sounds like I'm at least half way right
#5: I'd use RO/DI water and make the salt mix your self with the instant ocean or whatever other salt brand you like. RO/DI filters can be purchased from
The Filter Guys
When your salinty gets high, you can do a 1 gallon replacement with some RO/DI non salt water, always top off with fresh RO/DI and not salt, or you'll end up with high salinty...
1.024-1.026 is what I aim for and try to maintain my tanks at...
Hope the answers helped some for ya...