That is a long post indeed! 
Thanks for taking the time to explain all . 
So first of all, hope you dont regret typing half of that, but i havent even touched static lighting for one yet. The landscape isn’t final yet and i figured i’ll change the lighting during and after it is finished so i decided to go fully dynamic. The main focus is the car(or cars, who knows) and probably the only static objects are going to be the landscape and foliage, and foliage doesnt agree with static lighting so easily nowadays anyway.
The reason i skipped skylight is, you need to disable “Lower Hemisphere Black” in order to get full reflections without baking lights. Otherwise, the lower side of reflective surfaces get pure black when SSR can’t capture enough reflections. And when you disable it, you get the reflections but lighting gets blown up and you cant fix it with AO either, and if you reduce intensity then reflections go down as well as you mentioned. It also saturates the landscape more than i need. It is going to be a desert so LPV’s shadows looked good enough to me. The shadows look darker in the distance but it is a distance i can handle with atmospheric fog.
About LPV vs. Translucency…Here’s my bug report on that: https://answers.unrealengine/questions/35329/lpv-causing-crash-with-translucent-material-in-a-m.html
I don’t know what you mean by deactivating shadow casting on skeletal mesh parts, but i tried every possible tick box i can imagine and nothing worked. It is not a big deal at all though and it may even be something on my side, so, i’m just importing transparent parts as separate meshes and putting them together in the blueprint.
I can’t let the tail lights not cast shadows since their light leak to the rear tyres, but that console variable you mentioned got me curious. Is it r.StaticLighting=0? It doesnt seem to work for me for some reason.
Finally on materials, i worked with PBR long before UE4 so have no worries.
All in all, is a hobby project and has no deadline so i’m taking my time experimenting all possibilities. I’ll give static lighting a go as well once the landscape gets its final looks and keep you posted.
Thanks again for all the input and dont hesitate to make suggestions as you find more!