Going back to your OP, The belt snapped after the first test ride, I would venture to guess they adjusted the belt too tight which made it snap during the RT. That would explain that.
I would also look into the chain being set to tight which in my experience made some vibration at certain rpms. Now when you changed the MM that could give you more vibration from the eng/trans movement. I think the mount change compounded your issue.
Id say get the alignment and go from there, because the correct way to find problems is by process of elimination and since you had the belt and mm's off, you should clear up those areas first. I disagree with crank issue at this stage. Personally I would put in the HD auto tensioner on the primary.
The glide pro wont do anything for your vibration because you said it vibrates just raising the throttle when the bikes not moving, that eliminates the G pro.
This is my professional opinion.

 

Bagman,

I appreciate your help and thoughts also.

I have already installed the Auto Primary Chain Adjuster. The Svce mgr thought maybe my chain is getting some tight spots, and as the motor gets hot, the vibration kicks in from the chain, hence the vibs at certain RPMs while the bike is sitting still. This Svce Mgr is a fantastic guy and I believe he and another mgr have alot of knowledge. It also seems to gain a 'roughness' to the vibration after running for a few miles (hopefully that made sense!).

Thanks!

 

There has also been some suggestions of a rebuild, and bump up the motor to 95, cams, etc............ And if I had the disposable coin, I'd do it in a heartbeat.