They’re all in the same group called Time Keepers! I currently have it written down that they’re all scattered across time and are trying to reunite.
They each have different time related gimmicks (Melanie’s was supposed to be time stop, but we haven’t implemented moving platforms)
Aside from their cloaks, they each carry a pocket watch and share the albinism trait! You may have also noticed that their names are based on measurements of time ^^