Intflatable Dalek, re: River - not quite. Her comment of 'Spoilers' seems to imply that there's at least one more encounter between the earlier River the later Doctor still to come.
We know he still has turn up at her door withe a new haircut and a suit, to give her the sonic.
They're both time travellers, so can meet in any order
Oh, I'm sure they could have lots of off-screen out of order meet ups, it just felt like it was written as a final scene for her in the show itself. It'll seem a slightly OTT way of saying goodbye if she pops up again any time soon at least.