I do not think it is a good idea to continue driving since oil is leaking from rear drive unit. Did service say it was ok to drive or did they want you to tow?
We should start guessing the cause since we were left with no information.
I am guessing that location is off grid and that he had a gas generator with fuel can in the frunk.
While you are checking take out each bolt one at a time, apply blue loctite, tighten, and put a line on the bolt and panel with a paint marker. This makes inspecting easy because you can see if the bolt has rotated. It is a good idea to inspect after off roading and once a month.
I am just going by appearance. Also the factory rus panel is smooth and metallic. The panel you have is composite and even if it has additional metal plate underneath, the composite would get damaged if you go over a rock correct?