The first two pic show a case of tissue necrosis, probably due to poor water quality. I assume they are new for you, so check the PO4 and nitrates. If the PO4 is over 0,18, this is the main problem. I would recommend keeping them out of too strong light, as this may exacerbate the situation.
The last corals are A. millipora or A. prostrata, which are both very similar, with A. prostrata tending more to branching, while A. millipora is digitate. They look essentially healthy, but a bit dark in colour, which means too many nutrients in the water.
Check you water parameters and report back. If you don't deal with the situation, you will most likely loose the corals. Sorry for the bad news
