Adopted Oncidium needs help!

[orchid623]

A friend of mine gave me this Oncidium yesterday and since she recently cut the spike off, I decided it'd be a good time to re-pot it.

Well, I take it out of the pot to discover (of course!) a mass of mush. One baby bulb fell away from the others as I was picking out the moss from the roots.

I am currently converting an old pint-sized Talenti gelato container by punching holes throughout. It's just large enough for the roots to fit in (you can see it in the first pic). Should I plant the baby bulb with the others, or by itself in an even smaller container?

I see some scary black areas on some of the roots, but I don't have any Physan or brown Listerine on hand at the moment. Is there anything else I can or should do before I re-pot it?