Suppose the inhabitants of my village/town has just been enslaved by the Roman empire. How likely is it that i would see anybody from that village/town ever again?

This is a very interesting question, but honestly I do not know if we can say one way or the other. An enslaved village would be taken to a, to put it in slightly grim terms, "wholesaler", but the question then becomes whether the slaves would be sold on the market separately or as a "set". I flipped through the various agricultural manuals that discuss slaves and I couldn't find anything one way or another--they don't say, for example, to not buy slaves from a captured village because they might cause trouble, or do buy them because they work well together, or anything like that. Their only real discussion of origins is essentially stereotypes--eg, Thracians make good shepherds.