1) You can play the DL campaign from DA and you will have access to improvement-level spies (as opposed to DL's civ-level spying). So, yes.
2) I don't recall seeing any asteroid belts in the DL campaign, even when run from DA-and it would very much surprise me to see them, as the terrain for each mission is essentially predetermined (with the possible exception of bonus tiles on a per-planet basis). So, no.
