My bet is the front regulator has a broken nylon roller or two. That's why it's moving slowly. As far as the rear are concerned, usually it's all or nothing. Pull the Window Lift Ecu out and check the circuit board for broken solder joints. It's easier to remove the board that to remove the entire unit from under the dash. Unplug the two connectors (one white and one black), pry the plastic cover off the front of the unit and the circuit board will slide out. Inspect and solder. Plug the connectors in and test the windows before you button everything up.
I usually sell used ones that I've repaired and that come with a 60 day warranty for $50 includings shipping. I can't believe a new one is close to $300 these days. Also, look at Atlantic British. I think they were selling a kit for fixing the Ecu for a lot less than the cost of a new one.