Since Heroman has yet to be dubbed, I thought I'd show you people who I think should be involved. Here's who I'd pick:
Joey: Yuri Lowenthal or Johnny Yong Bosch
Simon: Steve Blum (he even kinda looks like Spike anyway)
Lina: Hynden Walch (Starfire on Teen Titans)
Professor Denton: Crispin Freeman
Holly Jones: Tara Strong
Will Davis: Patrick Labyorteaux (he played Flash Thompson on the Spider-man cartoon back in the 90's.
Stan Lee: Stan Lee of course!
Kogorr: Paul Dobson