Hi,
Due to the geometry of the model and how Unreal processes this, it may be difficult to find a workaround for the errors. Since this appears to be more of an archviz type project, I recommend looking into using the Datasmith plugin. This is geared towards archviz and would let you bring a scene that you have set up directly over into Unreal with materials. Importing your assets using this plugin may help avoid errors/warnings that you would get otherwise. Here is the link where you can find more information on Datasmith, as well as register for the Beta.
-Thank you