I can double-check my wiring diagram, but I believe these are separate problems.
The reverse lights might be the tranny switch. I have a manual, so no further comment.
The interior light issue is on my list as an active problem. The number of related posts indicate this is a common problem. Assuming the door switches are working, the culprit is said to be the so-called 'seatbelt buzzer relay', which does more than its name would suggest.
Another poster helpfully took pictures (thanks man!).
See
http://diesel.web1000.com/5/