Thanks, that worked for getting the IDs, and I think I was able to ressurect the goblins. Their corpses changed status to (h)idden, and then simply disappeared as soon as I unpaused the game (curiously, their severed body parts didn't disappear along with their corpses). But the goblins themselves were nowhere to be found, nor were they back in the units screen. I guess they respawned elsewhere? So I tried the same method on one of my dead dorfs (but via unit screen) and he reappeared where he was struck down.
So I'm guessing the goblins would also reappear where they fell and probably go into ambush state. However, since they died in various locations far from the fort (which I can't even remember the exact locations) I wasn't able to station my militia to cover all the suspected locations. The solution would be to use the teleport command. I tested it on a dorf and he teleported to the pos I had input. I tried it with the goblin's ID but they didn't appear at all (even though DFHack didn't output any errors).
Perhaps the goblin's ID I got was wrong or the full-heal -r didn't actually work. Either way, my fortress is still stuck with the perpetual SIEGE :-(