Mystery rubbing such as this are pretty much impossible to diagnose over the web. You need to start by helping yourself. Hang the bike up or even flip it over onto the bars and seat and then locate the source yourself.

Also a slightly scuffing disc brake does not cause vibration. If you've got some sort of shudder coming up through the bars while not applying the brakes then it's due to something totally non related to brakes. If the shudder occurs when you're applying the brakes then that's different. In that case your calipers may need to be adjusted or you may have a brand that comes with stock pads that are not happy with being wet. Full organic pads seem to like to squeal or shudder when wet. The ones with some sintered metal in them seem to do this less.