Katrina,

That pbulb that is still soft is unlikely to get healthy, so keep a close
eye on it. As far as the bright green spot on top of a bulb, if it's one
that has lost its leaves the plant may be growing a keiki; it's a
'life-saving' strategy for the plant.

Watering - I can't specifically answer your question about how long to let
it go. My best advice would be to put it on the same schedule as your other
Oncidiums that are doing well.

Good luck with it!

Diana