I guess that depends on what kind of animal would sing along to show-tunes, wear cardigans, and have an intense love of carbs...
Since I'm pretty sure that animal doesn't exist - though a parakeet might look pretty smashing in a tiny cardigan - I'm gonna say this guy:
Just kidding. He's kinda creepy. Like the Nosferatu of the animal kingdom.(But he is a real animal. He's called an "ayeaye". And appropriately so, methinks.)
For rills I'd probably be this guy:
Cuz for rills guys. Agile, quick, Sort of oddly adorable. That stache? Done.
If not I'd probably be a cat. But only if I could be The Bell's cat. They have a pretty good deal going on.