Thank you @BenPalmer and @robdyck, both of those options worked so I have a few options to choose!
1) Turn off roof plane layer, turn on roof overhang layer, uncheck "soffits" to remove double line on floor plan view. Only issues with this one is it will remove soffits on 3D views, which may not matter if this file is solely for the presentaiton floor plans and not renders, but it also still shows the roof planes on the dormers for some reason.
2) Create polyline around exterior, white fill, move to order 27 (behind room fill), move all roof planes to order 39 back (behind room polyline).
EmmaCox's post in Roof Plane Lines - Hidden Past Exterior Walls was marked as the answer