I was thinking abt how Crowely and Aziraphale figured out that they needed to switch and I had a thought. It would be pretty obvious that Hell would retaliate against Crowley, and even realatively easy to guess that they’d use Holy Water, considering that he used Holy Water to kill Ligur. But, based off the comments between the demon extra and the angels, it doesn’t seem like bringing Hellfire to Heaven is something that’s really been done before, and although you can see the poetic justice in it, it would be more difficult to predict.
Plus, Heaven didn’t have a trial for “Aziraphale,” right? They were trying to just straight up execute him, and I’ve seen some headcanons that they were probably going to lie and say he killed himself as penance for his treachery. If that’s how Heaven deals with shit, what if Aziraphale didn’t realize that Heaven performs executions like that? What if they didn’t realize “Aziraphale” would be taken?
It’s gonna be my headcanon now that they realized they needed Aziraphale to be Crowley, and that to sell the bit, they’d have Crowley be Aziraphale too, but they didn’t realize he’d be taken. After all, Aziraphale as Crowley seems genuinely panicked when they take Crowley as Aziraphale