Document, document. Those pictures are valuable, and keep track of all phone calls, emails, and other correspondence with dealer/manufacturer. Sorry you are faced with this situation, and we can feel your angst. The water damage potential is especially worrisome. The last thing you need is a mold situation. Is the dealer fully engaged in resolving these issues? I wouldn't hesitate to get the factory involved, too. Not to 'go around' the dealer, but to keep all feet to the fire. I have a friend with a newer trailer and a similar water situation, and he's been fighting issues for a year now. The trailer spent three months in the shop last winter, and his problems continue. Advise getting the manufacturer liaison in your corner, and we wish you a successful conclusion.
2016 Coachman Leprechaun, 319DS, Motorhome, Dodge Durango Toad