It's entirely possible to do side to side and forward back morphs for the jaw very convincingly. It's such a small transformation that the problem with morphs mimicking rotations problem doesn't become apparent. I'm too tired from work to show you example animations at the moment. This can easily include rigged mouth actors such as the tongue by using the match centers command.

That being said, I feel it's better to have a rigged jaw. I only know the above from creating mouth morphs for figures that don't have a rigged jaw.

As far as your actual queries go, why not try the Poser 11 technical forum? Nerd is a mod there, this sounds like something he'd be able to answer. He's managed to create weight map injections and knows a ton of related things.