Hey Paul, on the one that has rot, you're doing to correct thing, just make sure you get all the old dead stuff before you plant it, you may end up with only a few leaves left on the plant, but it'll be less likely to continue rotting.
The second one does look to me like pre-rot stage, like it has been in shade, and getting a little too much water. It should bounce back now that you have repotted it and are giving it the type of care it wants! Good luck!
