Can I use the same wash mitt on the wheels, wheel wells and paint?

It is best not to. Wheels and wheel wells carry brake dust, metal particles, tar and grit that cling to a mitt and can scratch paint if the same mitt is used on the body afterward. Use a separate mitt, brushes and ideally a separate bucket for wheels, tires and wheel wells, and wash them first. If you have only one mitt, wash the paint first and the wheels last, then wash the mitt thoroughly before using it on paint again.