What if Celestia and Luna decided to jointly adopts Sunset? Right after the fallformal with some legal documents and paper work. And Sunset Shimmer can have a family and 2 awesome mothers

6960952
there is already a story in development, it's called The Price of Wanting

6961417
But the thing is Luna is adopting her in that story

6961424
yes but both see her as a daughter and as they are sisters and not lovers so they reached an agreement

6961445
True, but if there were a story where Celestia and Luna adopts Sunset or be guardian's to Sunset