I hold the wheel and the stays near the BB. This lets me hold it centered and push back to keep the chain tensioned.
Tough to say about the noise. Sounds like you have a tight spot. Turn the crank and see if you can spot the chain tightening/loosening. If you find a tight spot, you can sometimes fix it by loosening the chainring bolts just a little. This will let the chainring slip over and reduce the tightness.
The seatpost just requires finagling or purchase of a cheap two screw post that allows fine adjustment.