If it didn't vibrate before you did this work, it must be one of the things that was changed. I'd run the car with the rear wheels up in the air and see if the driveshaft is running true. Why was the yoke changed? Is the driveshaft the proper length?
Whole car was put together from scratch. Nothings ever been run together. This is what causes the difficulty diagnosing it. Cant just undo the latest mod. I know one drum has a crack in the lining surface.This is why I was suspect of that.