Regarding NFC payments, the apps themselves refuse to run on non-vanilla OSes due to spurious security concerns and Google's maneuvers behind the scenes, but there are reports that Curve Pay works, at least in the UK.
I'll give it an install tonight. I'm curious to play around with it anyway and if I make minimal use of it, it should be pretty secure by it's use case.
I only mentioned NFC because you mentioned Google Pay.