Stop for one second.....stop buying parts and stop changing things and wastign money. Grab a cup of coffee, sit by the bike, and look at the chain and sprocket as a system. Theres not a thing wrong with your chain,sprocket, rear wheel, or anything shown in the video.
You have a brand new chain and sprocket that has not yet broken in. Over the first few miles, these wear into each other,and the mesh is smoother. Thats why you often times need to tighten a chain on a new bike, or one like this when you have replaced everything.
Look at that pad,on top of the swingarm. The one you tried to replace. Its there to protect the swingarm. That tells you that the chain can contact the guard,plain and simple. If they could get by without a protector, it would not be there. So, the chain contacting soemthign its supposed to contact cannot be considered a problem.
Your motorcycle is not electric powered. An electric motor generates constant power (in comparison). You are watching your motor way out of its normal operating range and the power pulses hit that chain and make it move a little. Its also a new chain and your master link is probably a little tight. That breaks in, too,given some time. Give the bike some more throttle and you'll see this smooth out. Still,it never gets perfectly smooth. If this motion bugs you, look at something shaft driven, or belt driven.
Look at this video if im smart enough to post the link. Watch this chain move. This is how it works. Why? It just is...
This is why Buell and some of the Harleys use belts to drive their machines, but we dont have that option.
You wont solve this because its not a real problem.