They both have the same pitch, but the #41 is wider, 415 is 3/16" wide and #41 is 1/4" wide, and might work better on a new sprocket...#41 and 415 chain are one in the same! check out your master link what side is the plate on ? and the closed end of the clip should enter motor first.
its a flat rear sprocket, and here is what happened when i tightened the chainIs the rear sprocket a "dish" shaped and not flat? If so, the teeth should bow away from the wheel, not inward. Just a thought. Last pic looks like 2 much slack and would cause jumping.
filing it on the sides or inbetween the teeth?In the pic, it big time looks like the sprocket needs filing. Might just be the pic. I have had two when coated, left sharp edges that made the chain ride up. I used a hand file and tested by walking the bike and watching and it took a wile. I have never seen enough torque generated to bend a frame the way yours did. If you look at pictures of other bikes, the tensioner is not that far back. But I honestly don't know if that is contributing.