https://www.youtube.com/watch?v=thDlCEuLzuY&t=517s
Edit: the two headed puppet can be seen at around 6:30
Here3 is a video of a two headed puppet, the two head functionality isn't talked about, but I have made one and I think there is another video out there by Dave where goes over making it work.
For live streaming, my puppet was very buggy, one of the heads would flip out and go crazy, but if you are just recording it works like a regular puppet.
Just make sure you Tag the second head correctly, (face, eye gaze, transform, etc.) and then arm/disarm everything on each head to make them work.
You can also change the parameters in the FACE behavior to negatives to make the heads move differently. Then you can record with both heads armed and they will both move, but in different ways.
If you really want a 2 headed character I think it's worth exploring. I always start out with simple shapes and colors to test the functionality before pouring lots of time in creating the artwork.
Good luck!