A) Elevator fixed:
1) Build an elevator foundation
2) Build an interior door or more if you need.
3) Build an elevator ceiling on the top of the elevator foundation.
4) Repeat from 2 for every additional floor you may need.
The elevator should now understand how many floors are above and if the shaft is blocked by a wrong part (like a common ceiling / floor panel) If it's blocked then the elevator will use the bottom part of the track if it finds at least one ceiling above.
If some part of the track is destroyed everything should be reinitialized
https://youtu.be/n8qQVswitGs
You can build the track how you want and all interior doors will open and close automatically according to the elevator floor.
B) Minor fixes all around.
Next update will be this Monday