rigging and tagging two independent heads on one body?

I think you can do it by adding two face behaviors etc, then only enable one at a time when recording. Puppets come with a default set of behaviors on the root. You could use one set for the first head (and body), then add a second set of needed behaviors for the second head (probably Face and Lipsync). You might need to place them carefully in the hierarchy so they find the correct layers (e.g. move Face to something above the male head and something above the female head)

The difficulty arises with the fact that CH doesn't like having more than one head label in the same object. I don't know what would happen if they were separate objects. Perhaps having two figures with identical torsos, one laying on top of the other, could give you what you want.