If they really enabled Apple Pay Cash in the betas of iOS 11.2, I‘m pretty sure that they also might enable it for iOS 11.1. No way, they let it test by developers or even public testers only.
With that being said, the emergency beta for iOS 11.1 made total sense now. It was the issue of Apple Pay Cash which was fixed in the last beta build of iOS 11.1. That’s why they delayed the last betas of macOS and watchOS.
Regarding new countries for Apple Pay: CreditCard companies like MasterCard and Visa start to “unfilter” the DBs for the respective countries.
Edit: WOW, they really let beta testers this in public... They really must be confident that this is working properly...