As a Demo of an Earth Angel character group, I will play the original three: Billy Butcherson, Thackery Binx, and Dani Dennison.
(Since Max and Allison are included as "extended friends and family", I'm just going to have Dani as the "Protected One".)
Zombie: Billy Butcherson. A young --as Zombies go (he was about 26 or 27 years old when he was murdered)-- Zombie, resurrected by the witches, Winifred, Sarah, and Mary Sanderson. After the defeat of the witches, Billy remained animated, and eventually earned a mausoleum for himself. Now, he has been recruited to protect his young friends, the 8-9 year-old girl, Dani Dennison.
Guardian Spirit: Thackery Binx. A young boy --also a victim of the witches, who changed him into an immortal black cat named, Binx. Freed, now, Thackery has been asked to act as the messenger for his friend, Billy Butcherson. Together, Zombie and ghost protect Dani.
Protected One: Dani Dennison. A girl of about 8 or 9 years of age. Dani met Thackery Binx when he was in his cat form, and formed a bond with him. Although distressed when his cat form died, she was reassured when his freed spirit appeared before her. She later bonded with Billy, and the two became closer. Dani was the first to defend Billy when his existence was revealed to the rest of Salem. It was natural to team her with both Billy and Thackery.