certainly there are hundreds of new + different .atr files in DS + IT
For example DS introduced 2 new Hero characters and the stats for the other Hero's do differ between GR/DS/IT
and as for enemy, friendly, civilian actors:
GR has 562,
DS has 364
IT has 434
The MP Actor files also change between GR, DS & IT
the only actor file group types that are only under Origmiss are those of the demolitions, heavy-weapons, rifleman, sniper. (and this is perhaps what you meant to say, as you were only thinking of the ghost actors)
Yes of course, this was wat I mean