I do similar work and I am assuming you have a demo system your company is taking to tradeshows and client sales meetings and whatnot that you are targeting. Not making an application clients will download and try to run on a phone.
If that is the case, you might be making this more difficult on yourself than need be. Since this is an industrial application, not a game, consider whether you even need to use forward rendering. The main reason for using forward rendering is to get acceptable performance across a range of particularly lower end hardware like phones. If you are using a high end gpu with a big chunk of memory like a 1070 or better, and you know that’s the target system the demo will run on, optimizations like forward rendering may not be necessary. The information you are getting, especially from livestreams by Epic, is game centric. The information is under the auspice that you are trying to make something run on probably a midrange system within a couple of gigs of VRAM or a phone. If you have 8-12 gigs of VRAM or more available for this application, use it. Disregard best practices for game development and maximize resource usage until something breaks. Use every feature you can and only worry about optimization when it’s clear you need to.
For your lightmaps, you can start by editing your DefaultDeviceProfile.ini and increasing the default Max LOD on your lightmaps and other textures to 8192. You can break your terrain into subobjects and give them all unique lightmaps to further improve lighting. If you need to, you can consider combining parts of the models where it makes sense to do so (objects that are close to each other and using the same material for instance) but I wouldn’t out of the gate start worrying about draw calls and combining static meshes based on what you have described. I would probably start looking at ways to instance meshes if possible with your data set if performance is an issue before doing any other optimizations.
I don’t know how big your scenes actually are, but you don’t have to work at whatever scale they import at. You can scale them down either before export or inside the engine if the scale is causing issues. Adjust the height of your player camera accordingly if needed. In engineering, precision is important, but if this is for client demonstrations/sales, it only has to look right, not be right 
For lighting, again, based on the assumptions I’ve made, I would try using deferred rendering, static lighting, and making the lightmaps as large as the hardware will allow. This will give the best visual results.