First, WELCOME TO THE FORUM!
Next a few comments about a few of the items on your list:
-two drawers won't stay shut on any trip---This is pretty common, has been discussed here on the forum a few times, and is not specific to Montana. We do a couple of different things, one--ignore it, like in the bedroom, when the drawer can only go about 2 inches before it hits the bed.
Next: velcro strips to hold the doors/drawers closed. Next: extra hooks on the inside or adjust the ones you have. We used to have a TT and would take bets on what we would find OPEN every time we opened the door. It was part of the adventure!
-snap on sliding door is not strong enough to hold door -- we found this happened too, and our fix was to shorten that plastic strap. Made it fit real tight, took out the slack. Has not happened since then.
-tank fill guages do not work -- check the search engine on the forum, this also has been discussed a number of times. Our experience, NOPE, they don't work much, and we do not rely on them much either.
-both axles bowed upward
-four tires bald on the inside
-brakes embarassingly noisy.
For all three of these issues, again, use the search engine here on the forum, another new member, just the other evening posted something about a recall on the brakes on 2004 units?? We have the same issue with our tires after 6000 miles, and we are not over loaded either. Within the last 4 to 6 weeks, a RV service person asked (on this forum) if people were having trouble with balding tires, see our post there about the subject. Note: these are all issues related to the axle and the company (Alko Kober) that manufactures them, in OUR opinion.
Congrats on having a great dealer! As you will find reading the posts here, not all buyers do have a great dealer. SIGH.
I'll let others tackle some of your other issues if they wish.
Cheers and Happy Trails.
Carol