Rob it's hard to answer questions without the machine details why don't you keep all the questions in one build thread and then others and me can follow along.

Do you already have some parts or is this supposed to be the complete setup for the machine.
In item 3 above he say he has priced for deep groove bearings the Angular contact bearings are much better. I also would be buying the motors from cnc4you as you will know what you age getting and they are tried and tested.