A screen cap of Beauregard, Rafter, and Eaves.
The Batz are a family of pink bats. The characters were also noted to be planned for a spin off series called "Batz".
Interestingly Belfry was from 2086 (noted in episode "I'll Be A Son of a Ghostbuster (Part I)"), so in a way his family/friends are 100 younger than him.