Hello izzy -- The Thinking about replacing oven with microwave
thread might be of assistance. It helped us make our decision. Yes, the oven is under-used in summer weather. It makes the trailer inside get so hot. I haven't become an expert in our convection microwave but Susie has a few things mastered -- like heating good bread so it gets hot at stays crusty.
I think the installed LP ovens are integral with the stovetop, so you'd have to find a separate stovetop and deal with the installation of each. The factory installed convection microwaves have a separate stovetop too.
If you are "about to purchase" I would say that all things are negotiable. So make the replacements a part of your offer if you still can. Be prepared to walk by having scouted other dealers.