Yes, all three will be in the show eventually and have already made small appearances in the pilot. There's not much out there since they're all either still being developed or being redeveloped but here's the t on them so far. Mimzy is a singer and club owner who died in the 1920′s.

Is mimzy in love with Alastor?

Mimzy. Mimzy's relationship with Alastor has been touched on by Vivziepop, though it is unknown what their relationship currently is. ... Prior to Hazbin Hotel, Mimzy was originally written to be Alastor's admirer and later love interest during the production of the show, though this idea was later scrapped.

When did Valentino die Hazbin Hotel?

He was suspected and believed to have murdered and trafficked over a hundred men and women from the 60s to the 70s. Valentino's reign of terror came to an end when his slaves managed to escape from his mansion, and he was subsequently killed shortly afterward in a confrontation with the police.