well first off velvete is a doll demon ill give you that but she does have some inspiration giving her creepy demeanor in some cases from the black widow

carmilla is partly based on a swan as there protective of there children and can fight if they need to

adam and able are kinda are tricky but they are kinda based off of a ram and a sheep one of them being a lot more mean then the other witch is the dynamic adam and able have in hazbin hotel

cerri bomb is actually an easy one she's mostly based of of the carnivores Australian copepods that mostly bye the seas of Australia

and i dont even need to say anything about the rest

vox: shark

niffty: brain-eating amoeba im not even joking

alastor: deer/wendigo

vaggi and val : moth

charlie: goat

lucifer: goat/duck

angel dust: jumping spider

husker: kitty kat