^Watto is, hands down, the greatest CGI character ever created, IMHO. The voice actor was an important part of that, of course. He had loads of personality. Keep him!
Zam was interesting as a female hunting another female. SW needs female characters that don't detract from the Leading Lady. I thought that, as a shapeshifter, there could be some dimensionality to the Jedi, as well. If Obi warned Ani that shapeshifters can alter their impression in the force as well as appearance, we could get a sense of Jedi power.
Edit: I am concerned, however, about such a radical capability as shapeshifting being introduced into the universe. I thought that maybe it could be limited to something a little more chamelion-like. A change in coloring, or course, and a "realistic" alteration of existing facial features.