Bib Fortuna: Already on the game. He's a Twi'lek.
Rancor Keeper: Isn't he human?
Spider Droid: Huh? It's a droid, not an alien as you said. Besides, what's that? Is it the spider-like creature on the shadows, right at Jabba's front door, after Luke comes in on RotJ?
Still, yeah, the more aliens, the merrier. Obsidian did a great job on implementing Sullustans on K2, their voices were perfect.
And Bioware used the aliens skins poorly. I mean, we only get to see a Quarren once, at Taris.