3ds max to UE4 - beginner questions about best workflow

Hello Everyone!
I’m very new to UE4, I’ve just followed the awesome tutorial by Chris Jennings “Creating an Interior Walkthrough in Unreal Engine and 3ds Max”, but now i need some tips from you

For example, yesterday I modeled some pieces to build a depot/hangar/warehouse (I don’t know the correct name in English).
This scene is composed by many modular meshes.
Here my doubts:

1: It’s better to import the basic meshes in UE, set their material and then build the model in unreal duplicating and snapping those meshes, or importing the entire warehouse from 3ds max, or maybe… something else?

2: Groups: in 3ds max I use a lot groups, but when I import them in 3ds amx, they are obviusly just meshes… which is the best workflow? Group them in UE4?

3: I just unwrapped everything, to be in space UV1 in Channel1… it’s ok some think like this?

By the way, I just ask you how do you guys would approch properly that kind of level design, to work without wasting time and in a clean way.

Hope this thread will be useful also to someone else!

Thank you for the tip!
Yesterday I finally found time to try this, tried with separate pieces and luckily it looks ok, i’ve tried the FBX Scene Import (it looks very useful) but I had some problems with meshes in different location compared to 3ds Max (probably some pivot/trasformation of objects were weird), but with the standard import everything was okay.
Next time i want to try what you say, build a complete wall piece all in a mesh with different ID!
Here the first result, I’ve already learn ed a lot of things. Thank you!