Strange door lock problem, general module?

[boostd92]

A week ago I picked up a 2001 X5 3.0 for a steal because it needed some engine work (separator, VCG, OFHG, Tstat, DISA, CVboots) but was in otherwise excellent condition. Previous owner shelled out serious cash at the dealership over the first 120k and the underbody (F&R susp, bushings, arms, ball joints, etc) is practically brand new and the car drives perfectly after fixing the easy engine stuffs..

I had to put new door carriers for both front doors but prior to this, the right front door lock was a little slow to respond, and sometimes didn't unlock at all. About 2 days later it just didn't work at all. So I have a friend at the dealership and got a brand new RF actuator and installed it and still nothing. So a buddy tells me to pull the door harness connector at the A-pillar and look for corrosion. Sure enough the botton 3-4 pins on the connector had GFS. I cleaned them out and reinstalled and still no RF actuator response. I ran out of time and put the door back together (with the old lock actuator), and checked it again and it was working!

At that time I figured it must have been a connection issue and it's finally seated. Fast forward another day and it seems the RF actuator works fine but pops up a little slowly. But the kicker is that the LF door lock is now intermittent! All of these checks being performed with the remote key.

Another thing I noticed: when working the locks with the central locking button, the RF seemed slow to actuate. After pressing the button several times in a row, the locks get faster and faster until they all operate quickly and at the same speed/time.

Could this be a general module problem? FWIW, all windows and other door functions work fast, and properly.

I also have no working rear defroster or rear wiper and an intermittently working rear hatch release button on the tailgate. I'm suspecting a wiring break in the hatch for that, but thought I'd throw it out there.

Thanks for any insight!