I live in 1990 low end single wide mobile home. I am trying to remodel, starting with bathroom. Because there are only 2 joists, I plan to attach 2x3s to existing joints and 2x2s to wall to create my own joists. Then attach tongue and groove panels 3.5 inches wide, treated with stain and polyurethane. New ceiling will simply be 2 inches lower than existing ceiling, keeping same angle. My question is about exhaust fan. It is a ventline 2062. I will need exhaust fan 2 inches lower than it currently is, and was thinking of replacing it with a newer model, that I can easily replace (same duct size and wires). I think 2262 is the same as I have, just newer. Will I be able to put it in with the 2 inch drop in ceiling and would I need anything additional to do this? I appreciate any help. Thank you.

Hello. An inspector asked that I repair the breach in the fire barrier between the garage and living space (walls and ceiling). Now, my question is, do I only need to do the ceiling and the walls facing the living area? Two of the walls face the outside of the house. One is the door wall and the other is the east side of the house (next to the outside). I tried reading the code, but I wasn't sure. Thanks in adviace!