It's hard to say what's already happened with your tickets with the cancelling of the other flight. If you miss your connection, you will get rebooked on another flight, in First. HOWEVER, if there are no Award seats on that flight, they will have to put you in non-award seats... which in my past experience means you get miles! Of course, if there is no F inventory there is none and they will deal with that accordingly...

This is why they will avoid changing your itinerary unless absolutely necessary (like a missed connection).

Last year this happened to me where one of my flights got changed and I earned miles the entire return trip. On my trip to Australia in a month, on the return leg the flight changed and my ticket is now an F ticket instead of X or Z. Wooohoo! Double miles for a trip I didn't pay for! And to make things sweeter, that A/C is now a 777 Atlantic config