My vote stands alone.
Listen, wise people, if you can't decide who to send off, why not send off someone who won't be important either way? Sauron barely did anything under Morgoth's rule, he sent his army one by one to their death and then he was easily defeated by a
dog. Huan was not a Maia, Huan may have been great, but he was far from a Maia.
It's a win-win situation. If Sauron goes, one less villain. If Sauron goes, Morgoth will fill Sauron's position with one of his Balrogs. Durin's Bane, anyone?
Send off Sauron, spirits of the Barrow-Downs.