Render people separately for later compositing

Hi all,

I am trying to do some architectural visualization and would like to render my humans separately, because I need some motionblur and transparency on them. If this can be done directly in UE please point me to some learning resources.

If not - My question would be how to keep my global illumination on my render people intact, while I switch off the room geometry. Is it possible to bake some light probes and light my humans with them?

Thank you!