Yes, EVERYTHING is coming out. Down to the studs. My current plan is to gut the place, replace ALL the luan panels with new. On the subfloor, The entire floor is one piece particle board like what a desk is made of with 2 large patches in it. My plan on that junk is cut it out in 4 ft sections and replace it with plywood of same thickness. Before I cut it out, remove the screws, mark the locations, cut the old out and remove then slide new in and re-screw. They build the floor in fullsize trailer houses like that. One 4X8 sheet at a time. If I understand correctly, none of the walls internally are load bearing so it should be fine. Not really on a time or financial budget. Not going to cut corners and sacrifice wants and needs over something.