If you can afford it, get a new disk. If you are on a budget, you could probably get away with using a sanding flap disk on the bad spots.
I run a set of tubes in an old set of paddle tires myself, just to get the most use out of them. It doesn't hurt anything except for the few extra ounces of weight and that if the tube slips in the wheel, you will shear off the valve stem.
The Motion Pro should work. I don't see why not?