Nat has TAC's vouching for being town so I buy her claim too. I don't think this was a 200 IQ mastermind play devised by a scum TAC and Nat to town confirm each other. I was also town reading Nat before TAC's vouching anyway.
This leaves Fuji who's claim is the most suspect of them all. Out of all the claimed blockers, he's the one I lean to be scum.