Ok listen up boyos I have the inside scoop on the backstory for the legendaries. You're gonna want to screen cap this.

You find Solgaleo/Lunaala in an abandoned lab and they are only husks.

Once you awaken them they tell you about their past and that they were once humans and they realize one of your rivals looks like someone they know and then presumably they know the league champion and she shows up.

Also Solgaleo can run through the sky and can shoot yellow beams from his paws so Electric typing is confirmed.