I think they expanded Tokyo but previously that was a single-building "region"

And it's virtually impossible to make, say, a Singapore region resilient to natural disasters

Did they claim Tokyo was more than one availability zone? If the 'tokyo' region was only ever claimed to be '1 availability zone' I think being in a single building technically still satisfies my quote above.

But yes, agreed.

Yes, in the API you got multiple AZs.