That is too bad all of this hitting at once
You should be able to check the hitch for under adjustment by comparing before and after fender measurements. IIRC you use the Husky. Page 11 of the manual.
With the roof, did you examine all of the seals and caulk? The cabinet over our couch has a number of wires going through to the walls and ceiling. Pay special attention to the caulk on those. I'm afraid I have no ideas regarding the leak in the lower cabinet next to the fridge and agree with Turbo to fix that and the others ASAP.
I tied down the water lines and cushioned them so they would not vibrate against wood. Your pump should also be fastened in the cabinet with a piece of carpeting, but if that is not working to quiet it down, you can use a nice solid piece of foam instead.
How bad is the damage to the bunks? Did your brother pinch material in the seals?