I'm wondering if I use white mmf to cover a chocolate covered cake if the chocolate will bleed through? I've always used white buttercream for the surrounding of the cake, but I'd rather not this time if I don't have to. Suggestions? Comments? Please?

I've done it with no problem. I do crumb coat, then a nice layer of buttercream, then fondant.

You definitely can. Just be sure your fondant isn't too thin so you don't see the chocolate through it.