Update:

Since the little frog was staying small (there were two little froglets, but one must have had a growth spurt), I went ahead and separated everyone into containers (little froglet in one, froglets and frogpoles in the other, and the tad in the 'mothership.') I'm getting their hides ready tonight so I figured they could get used to cleaner water and a little greater depth tonight before moving over to the tank in a day or two. There was a little bit of drama with the move but nobody jumped out of the cups or ended up out of the water which was good.

Do I need to be worried about the small froglet getting lonely? I know they don't 'need friends' but they are rather sociable frogs, aren't they? And they were getting along quite well together. I suppose it can't be helped either way as I don't want the little froglet to become lunch.