realisically there's only a small handfull of stories Disney could even use as source material for an LGBT princess movie, and unless they make up their own all the ones I know of are male/male romances (and not very good ones)
"the Princes and the Treasure", : a story about two men who set off on a quest to rescue a princess, then realize they're gay for eachother, (the princess then reveals she orchestrated her own kidnapping specifically to run away from a marriage she didn't want), then they both become Princes........somehowww?, and have a gay wedding(note: the illustrations in the book are specifically drawn in a Disney art style and the book was used as a Prank several years ago, claiming that Disney was developing a movie based on it, when they weren't)
"King and King" : a story about two Kings falling in love....that's about the entire story
"the Bravest knight who ever lived" : a story about a Knight who rescues a man (the Prince) and his Sister (the Princess) from a Dragon, and is offered the Princesse's hand in marriage....only to turn it down and instead ask for her Brother's hand in marriage instead (there's no implication he's gay before this, the story literally springs that he's gay in at the last second)
there were other Stories they could've done LGBT interpertations of....but they made movies of most of those as hetero love stories already, the little mermaid being one (the story was literally written by a Gay dude after his crush/possible lover left him for a woman)
there's also people hoping they make Elsa Gay in frozen 2......but......that feels like a cop-out to me, to just make Elsa a lesbian in a low-budget straight to video Disney sequel (kinda like Making Cinderella's sister Anastasia nice (and a great deal less ugly)in Cinderella 2 out of nowhere)