It's possible, but most likely if that occured the damsel was already ailing in some way.
Many times a clown will drag a sick/dead fish into a nem, making many think nem just ate a healthy fish.
You may see bones.
Agreed. There are several species (as well as larger specimens) that can take down healthy fish, but this species isn't usually a problem. Not discounting the possibility, but as davocean said, it is more unlikely.
Definitely possible. What species of Damsel? Several will actually host in anemones when young, Dominos for certain as I experienced that one for myself. Maybe it tried to host unsuccessfully.
Young or old, damsels can take a nem as host, but I suspect the missing tail MAY have had something to do w/ it.
Clownfish are in damsel family BTW.
My green chromis addapted to my nems.