Potty training is something that is very individual to every child. Some are ready before 2 and some aren't ready until much older. Has he EVER shown interest in training yet? The rush will be on now as he can't go to school unless he's fully potty trained. Sounds like you have a good routine set with training so hopefully after awhile in your care, it will come to him! I agree, that maybe waiting a week or so with him would be good though. Let him adjust to you and feel comfortable before pushing the toilet too hard.

As for changing...I'd change him standing up! That's what I do when they get too big anyways.

Good luck!