It was (fortunately) somewhat less work than I feared. I was able to remap the Selkath body to a scaled up version of the Human rig (Selkath are freaking huge). I had to replace their giant hands with modified Human hands so they would animate properly with the new rig. I lopped off a couple of the fingers so it was the same configuration:
I also got the UVs in the wrong spot, but that's easy enough to fix. Edit: Fixed, or at least approximated as close as possible based on a completely different unwrap:
Here's some combat. I edited the UTCs to give them a mix of sabers and some appropriate melee feats like power attack, flurry, critical strike:
The only real problem is their giant fish head is so enormous that they have a tendency to swing their weapons right through it. There's not much I can do about that.
Here's some dialogue:
Naturally using a completely different rig and supermodel, they no longer have the specific conversation animations of the regular Selkath, like the stroking of the mouth flap thing (cephalic lobes, if you want to get technical). The mouth is a bit stiff and flappy at the moment as it is only using head and jaw weights. I'll have to see if the original can be more closely mimicked by including some of the other face bones. The lobes no longer have bones and specific animations, so I was thinking maybe they could be cut off and changed to dangly meshes.