i headcanon phantoms to be the ancestors of the dragon or some type of baby dragon. I think they were hunted to (near) extinction before steve, alex and the others came around and they're only now coming back.

the hc is based off how endermen used to have green eyes rather than purple, and since phantoms eyes are green, maybe they're the originator to the ender dragon :3
Bats are probably related to them and the dragon too, but more in the same way a chicken is a dinosaur LOL