What could it be now?

mechanical question- 1996 XJR replaced drivers door latch & actuator (used) - the rear door decided to stop locking & unlocking before we replaced the drivers door part- what could it be?
also the trunk dome lights & ourside button stopped working at the same time. Coincidence?

Probably not. I would check all of the fuses (because it is easy!) . Then, logical troubleshooting. Your description of the sequence of events seems a little confusing. Is this really the sequence you mean?

  1. Front door part quit working
  2. Rear door quit working
  3. Dome and outside button quit
  4. Replaced front door latch

I suspect you meant to say 1, then 4, THEN 2 and 3. Right?