Porky is the studio head and Daffy is a talent agent. Still a showbiz setting, but Yankee Doodle Daffy doesn’t indulge in the same kind of fawning, straining caricatures that usually larded this kind of picture. The result is that it works much better.
The key is probably that these caricatures—Carmen Miranda (wow!), Al Jolson—have some function and weight. They’re not cutaways or name drops. In fact, Daffy actually turns himself into these people, and in doing so pre-figures the practically omnipotent character that Bugs was about to evolve into. Bugs kept it up, and the WB animation apparatus decided to pull Daffy back, or maybe push him into another direction. That’s later though. For now, this isn’t fawning H-wood referentiality, but a manifestation of this character’s protean nature. He’s simply not subject to physical law or the limitations.
Cartoons, in other words! Daffy is also anticipating and acting like Foghorn Leghorn, not only refusing to let Porky get a word in, but also blocking the guy he represents from actually doing anything. Except lick that lollipop, which is variably and repeatedly funny.
There’s a felicitous nightmare component to the film. Eventually Porky tries to escape the ministrations of this relentless creature. But now Daffy just keeps showing up everywhere, like Tex Avery’s Droopy. The daffy-as-parachute gag is funny. That Daffy’s client has such a big baritone voice is also funny, and it anticipates a similar disjunction between what we hear and what we see in the historic One Froggy Evening.