Don't use grease as it attracts dirt and dust! A much better product is dry lube spray wax. You are 100% correct to pull the rubber seal and scrub it out. I also recommend that you strip down the electric motor. Also possible is to swap the motors Drivers front to Passenger rear and vice versa.
I did away with the window attachment rubber, I cleaned the track out thoroughly filled it partially with sikoflex taped the glass to the track making sure its in the correct alignment and position left it fir a few days to cure and reattached the window into the door . This method is used by window replacement companies they don't fit the factory rubber. They window companies refit it before it's cured drive the window to the top and tell you not to use it for 4 days. I prefer to let it cure first then refit it .
