Oh yeah the wierd one is 10000% a porcelain crab i saw the wiskersThe feathers means it is a porcelain crab for sure. As someone else pointed out they are completely harmless. They're one of my favorite crabs since they will not harm corals and fish at all. They scavenge and filter feed. I know there are several species of porcelain crabs, but they are all similar. I know some really enjoy anemones to live in and around. I know the lighter colored porcelain crabs inhabit anemones.
As far as the other crab, it's pretty difficult to tell. Might be an emerald crab