'If they are offset, which is normal for most motors now, that can totally be reversed, which will offset the rim to the brake side, and give you a good bit of clearance. It does involve taking the motor apart, but nothing more complicated than taking the side cover off, pulling outer ring off, and slapping it back on in reverse.
With that done, you probably can make the rest of the adjustments with just a spoke truing. no re-drilling or new spokes should be needed"
Have you reversed the covers yet? I'm really interested, simple and affective.
7 speed chain 1/2 x3/32
9 speed chain 1/2 x 11/128
So yes you will need a 7 speed chain KMC Z51 $15 at any bike shop
Chain ring? If your running a single you should only see an issue under a load if you are you using a entry level derailleur. If you can find a old stx it would work nicely the few times you use it. If their is ever a problem with the chain jumping off the chain ring put on "any" front derailleur and your good. If your running a double or triple change them out and you will not need to it in future to rule and a problem. My opinion