It sounds like u could could cook up your own flash shelled uwp prog and side strap it to a wp in dev mode. I'm gonna try this with a few old flash games when I have the time.
https://msdn.microsoft.com/en-us/windows/uwp/porting/desktop-to-uwp-run-desktop-app-converter
That let's you turn exe's(win32) into uwp's... So the idea is that you package up a flash game with fp standalone and then run it through the desktop app converter. But this is using fp as a game engine. Not a multi media player plugin.
The problem is that it's all backwards and your putting shells into shells and fp and most flash games are resource greedy to begin with. :( but saving cool games, even flash games, is always worth a few hours of trying.
At any rate...
Moliplayer(that's really the name of it... Snot a typo...) app on winstore supposedly let's you run flash videos, but I havnt had a chance to fully test it. It gives you a browser that let's you save flash videos to you phone. Then you load em from there.