Re: potty recommendations?
We used the Baby Bjorn little potty and the Baby Bjorn larger molded plastic potty, both of which worked well. I imagine the Little Potty is probably too small for your child (though my ds used it until he was about 3.5, it was just what he was used to). The larger version didn't seem nearly as comfortable, but it was definitely better suited for a taller kid.
That's all of my limited experience.