Yeah, lighting and shadows is a big deal that I haven't made any breakthroughs on. Currently I try to replicate the lighting setup in Blender when you tick 'Include lights for Cycle' in the MB-Lab menu with four spotlights of varying brightness around the character - the result looks nothing like how good it looks in Cycle of course. Any idea what lighting setup would work better?For lights, I see you're lighting the scene flatly. There are little to no shadows in the scene. This kind of lighting, in my experience, will make any shader, no matter how good it is, looks like sh*t. The only thing that can help with this type of lighting scheme is Ambient Occlusion, or SSAO for the realtime version. This is just another type of shadows, and it uses tons of CPU/GPU resource. IMO it's better to re-setup the lights before resorting in AO.
The thing with the shader is Mb-Lab doesn't really provide game-ready texture maps either: you get a very orange diffuse map that needs color adjustment in photoshop, a bump/ height map and a bunch of height maps for muscle, wrinkle and fat folds that needs converting into normal maps (admittedly, a proper 3d artist would do a much better job than me with these conversions), etc Combine that with the difference between Cycles rendering and realtime rendering and we end up with the characters looking like 30% as good in game as they look in Cycles renders. That's why I was delighted that the new guy in charge of Mb-Lab is an Unreal Engine user himself and has already made efforts to make texture maps