My daydreams are still on this "cerberoids are cute" kick. That's the name I've adopted for them - the three-headed canid shape - although I also sort of like lowercase-c "cerberus" as a species as well, analogous to lowercase-p pegasus. Cerberus and Pegasus were specific individuals. Cerberoids, though, would be the more general "anything canid and three-headed" ones. I guess you could even go to "cerberiforms" to extend it to ursines, mustelids, and so on - anything caniform.
@bj three is probably my second favorite number of heads after two.
-F