So I had a Fortress that got attacked mid-bridge construction by a Werelama. I thought it had killed everyone stuck outside, but it seems it bit a dwarf child.
Not being able to command the child to seal them away, and the fort being pretty young (not even dug bedrooms yet) I figured I'd just abandon and reclaim instead of dealing with a constantly shapeshifting murder child. I'd already lost a few dwarves to opening the caverns too early to get water, so reclaiming with some less-traumatised dwarves would be useful since the basic embark seemed like a good location. And the world is neat too, a 75% goblin population with the elves, humans and dwarfs all forced into the bottom left corner of the world by the aggressive goblins, not that things were helped by the humans and elves waging constant wars with each other.
Abandoning turned out to be a mistake, as it seems either a lot of my dorfs were bit without me noticing or that if you abandon with a were-creature, most of your fort turn into hostile werecreatures that haunt the halls and constantly ambush any reclaiming dwarfs.
Needless to say, all but one of my reclaimers were killed or hospitalised. Fortunately I sealed off the caverns before abandoning, and it seems like the majority of werelamadwarves were spawned in the cavern and busy ambushing cavern creatures beyond reach of me. Armok help them when I decide to open those caverns though, which I need to do at some point since the cavern is the only source of wood on the map.
So now I wait, with the one furnace operator diligantly cleaning up and tending to the hospitalised dwarves. Waiting for migrants to come, clean up the random items around the fort, and form an army to raid first the caverns, then the neighbouring goblin towns (the whole reason I wanted to start the fort).