They might have kinda-sorta ripped off Monkey Island's music in that one place, but it sounds like Michael Land returned the favor; the track used in the underground salesman-world (and heard again at the end as you're giving out the awards) reminded me of the beach club theme from Curse.
Also I was thinking Roger Rabbit when the purple dragon started talking. But I do kinda hear the Ed Wynn similarity. I remember back in the very early days of Rob Paulsen's podcast Talkin' Toons, they talked about how voice actors trying and failing to do an impression has sometimes led to an iconic performance in its own right. "A bad impression is a new character" were the exact words. That's stuck with me, and now I wonder if that's what happened with Roger. Wouldn't be the first time someone's impression of Ed Wynn has been bad enough to become its own thing.