i headcanon that fawful used to work with e. gadd in the past, before he went insane. and once fawful met cackletta and became villainous, he used the concepts he had worked on with e. gadd to create his vacuum helmet, while E. Gadd used it to make the Poltergust series. that would explain why both use vacuum based inventions that are capable of sucking in spirits. it also explains why E. Gadd has a connection to the Beanbean Kingdom. I definitely feel like there's no way Fawful wasn't at least loosely inspired by E. Gadd design-wise. they are both nearly-bald scientists with swirly glasses who are physically small and frail, and even have similar voices.
