This is something I happened to look up myself earlier. The rules for Interacting don't mention other figures, so you would be able to interact with a token below a figure.
I would also like clarification on this. There is one mission with an AT-ST, and I'm wondering if I can just park the AT-ST on top of things so that the Rebel players cannot interact with it until the AT-ST is destroyed.
(that would be a really mean thing to do, but so far, I am unable to completely stop all of them from winning 2 missions in)