Welcome to TRT!
How long have you had the leather coral? They can be finicky at times, especially when just moved. They may withdraw their polyps for days at a time and then get a layer of "slime" on them which they eventually sluff off. This is how they grow. They need some flow to help get this layer off, so when its tentacles are extended you should see them waving a little in the current.
As for the anemone, it is going to move around until it finds a place that it is happy in. Sometimes they do get caught up in powerheads and it can shred them. The trick is to turn off the powerheads for a little while and let the nem try to settle in. Once it looks like it has found a spot, then turn the powerheads back on and see if it stays there. A little trial and error I am afraid.
Without knowing anything about your system, how long it has been established, what your water chemistry is like, what other critters are in the tank, what size tank, and so forth this is the best I can offer for now.
Hopefully someone more knowlegeable will respong to your questions shortly as well.
