Some final thoughts, questions, and what I learned.
I learned that the 3M 90 and Liquid Nails Fuze*it adhesive are great products. I tested them on a few surface combinations. The Fuze*it is amazing. On wood to aluminum, the wood will rip/split off before the adhesive fails. It will glue almost anything to anything wet or dry. The 3M 90 spray adhesive is about 75% as strong but gives better coverage for large flat surfaces and has an almost immediate grab time.
I also learned that concerns about puzzle piecing luan into the sidewall are unfounded IF you secure the luan to the frame by using glued and screwed wood bracing attached to both the luan and the frame. And, of course, the luan is securely attached to the exterior filon.
the mismatched paneling I put up is a different animal altogether from the original panel. The 2 pieces pictured were put in a glass of hot water and allowed to soak overnight. I wanted to see if I could lift the vinyl covering. Water did not phase them in the least. This should be in all RVs.
this repair was time-consuming but not technically difficult at all once I had the proper adhesives and panel. I assure you it is the strongest wall in the MH.
The most confusing part was removing the window blind.
The most labor-intensive part is removing parts of the original paneling that are intact. That is why I did not replace the entire wall with the new paneling.
I will decide if I want to overlay the lower half of the wall with wainscoting or cedar paneling so I don't have the different molding pieces. (Fighting my OCD).