My first real ARCH VIZ to UE effort (lots of pics) Advice needed please!

This is my first project doing a ARCH VIZ model in MAX2018 with the intention of bringing into UE to produce a VR on a hillside terrain.
Some background info:
I modeled this in MAX because I hate using stuff brought from REVIT and other CAD/BIM programs as the geometry is usually messy and way more clean up than I care to do. Even with the easy button type software like Twinmotion and Lumion. There are still things that seem to always cause me grief and frustration.
This was modeled using spline and simple box modeling to reduce as many polys and faces as possible except for the darn railings. I do NOT at this time plan to allow the user to enter the building to explore it as there is really not much to show but offices and a reception area in front and auditorium in the back. (Maybe some time in the future).
My questions are these to start:

  1. I am not sure if I should UN Wrap my geometry now for light maps or just let Datasmith handle it? Again I really do not like using automatic stuff that I really cannot control,
  2. How do I decide how to group or break up the model for texturing and unwrapping? Take a look at the pics please.
  3. How many draw calls are too many? 5, 10, 20?
  4. Becauseof the size of the building, I was planning on 2k and 4k textures for things like walls and roof surfaces and everything else no lower than 1024. Is that going to work?

I can share the model if anyone wants a closer look and maybe help me with mesh organization…