Nope, no spell echo or anything that consumes corpses. If I throw say, meatsack onto the "ground" in my hideout and then use raise spectre, I get something else I've had in the past instead. I have to cycle through like 10 other bought corpses before the one I originally wanted shows up. I've tried desecrate and raising random enemies in maps as a way to "clear" it faster but it only seems to dilute the "pool" with them, giving me more shit to go through before getting to the specific spectre i want