So this is one of the most debated things on here (right next to Starleaf/Brackenleaf), will future black foals have starfire? Here are some of the reasons why or why not they will have starfire:
The prophecy thingy was fulfilled by Star, so there's no need for another pegasus to receive starfire
All black foal should continue to receive starfire because that how always worked
Black will become a common color for pegasi, but only those sired by the hundred year star get starfire
No more black foals will be born, unless they are a direct descendent of either Star or Nightwing
but what about in 98 or so years, when the hundred year star comes around naturally?
I was just listing some of the things I've seen multiple times