A scolymia (button coral) is considered part of the "brain" coral family.. like a lobo.
Candycane corals are usually considered a beginner coral. They don't require a lot of light, are fairly easy to care for, but they do like to be target fed when the feeder tentacles are out. In your picture now, they are closed up, but at night you will see a ring of clear tentacles come out for near the edge of the coral. When you see that, get some mysis shrimp, thaw it in a cup of tank water, and use a turkey baster to gently squirt food onto the coral. The feelers will catch/stick the food to them and the coral will eat it. Candycanes really do well when you target feed them and while it isn't considered a requirement to do so, it is generally accepted practice if you want it to look very healthy and multiply. As far as the coloration, it looks fine to me, just look like a wild Candycane and not a fancy super neon green candycane you see at stores some times.
For the aiptasia, your going to have to at least do some chemical method.. kalkwasser, Aiptasia Control, etc.. any of those products out there for that purpose work somewhat.. nothing seems to ever work 100% though when it comes to chemical solutions. What I have seen people do is a combination of chemical and biological, ie, squirt the aiptasia with the chemical to get it to shrink up and kill as much as possible, then 24 hours later throw in some pepermint shrimp to eat the rest. Pepermint shrimp usually don't eat the BIG aiptasia like you have, but if you use some chemicals to start to take them out the pepermint will usually finish the job. One word of caution though, shrimp are pretty sensitive creatures and usually do not fare well at all in newer tanks.. tanks less than a couple months old.