Best way to cure Ich:
Remove ALL fish to a quarantine and treat it with copper, then let the aquarium run fishless for about 3-4 weeks. This will solve your Ich problem.
The Chloride molecules bind to the gills preventing the Nitrite molecules from getting absorbed by the gills into the bloodstream. The reason Nitrite is a bad thing to have is because Ammonia is often present at the same time, which will kill fish.
When it dies it will basically dissolve and nuke the entire aquarium, so it would be best to remove it. Doesnt look like you are using enough light for it
Anemones will move around to a spot they want to be in, if you find it in a certain spot it wants to be, moving it forcfully is a bad thing to do. Thats the thing about having a living animal, they dont tend to do what you want them to do :)
If you get a fire worm do NOT touch it with your hands, since its basically a bristle worm, but its hairs will give you bad rashes and alot of pain (hence the term "fire worm")
It depends on what you want to have in terms of if you need a skimmer or not. If you go reef you will almost be required to have one, the degree of success depends on what type of corals and inverts you want to have, how big your aquarium is, and how much Live Rock it has.
My advice is to...
In terms of cutting starfish, most starfish need a complete leg and a portion of the central disk in order to regenerate into a complete animal (this is because if it has a portion of the central disk it can still get food otherwise although at a limited degree, otherwise it will be on energy...
In Saltwater any detectable ammonia is toxic.
The aquarium is too small for the tang becauce they are very active swimmers, so need alot of swimming room.
Dont bother using fish to cycle the aquarium, you can use the pure ammonia method or use the raw shrimp method to cycle the aquarium, and get much better results.