Yeah, the three main dignitaries (Sim Aloo, Janus Greejatus, Kren Blista-Vanee) are clearly humanoid, but from a different species than the Earthlike humans seen filling the Imperial ranks in the OT. In reference materials they're sometimes referred to as "Coruscanti" but little or nothing else is said about them or their origins.
What do you base "different species than the Earthlike humans" on? I see nothing different about any of the five members of the Inner Circle seen in ROTJ compared to human members of the Imperial Navy.
Old Databank pages on StarWars.com, by the way, called at least the first two individuals simply "human." Aloo was from Coruscant (and prevailing thought in the current EU is that humans in the GFFA originated on Coruscant), while Greejatus was from Chommel Minor (where he gained prominence / notoriety as an anti-alien politician in the Old Republic).