For some context, these are the characters switched in the au:

[og character] with [character who is taking their place]

Greg The Dog with Zuzu

Officer Knight with Officer Milly

Petey with his mom/Sydney

Grampa with Sydney's mom (OC)

Li'l Petey with Li'l Sydney (OC)

Chief with Sarah Are switched

Yolay and Nurse Lady/Genie are switched

Molly and Flippy are switched (the tadpoles are now butterfly fishes)

Naomi and Wendy are switched

Melvin and El are switched

Big Jim and Bub are switched (everyone thinks he's a cat and put him in cat jail like are yall THAT stupid 🤨🤨 /ju)

Piggy with this random silly cat i found (I'm naming them Margaret :) )

I'm not really sure who Crunky would be *sobs /j*

Anyways, that was just for some random background knowledge :) hope it helped!