NOTE: This is speculation, some might say wishful thinking. I’m not siting sources, just offering an opinion.
Star Wars movies have shrouds of secrecy around them, it’s a given. It isn’t just JJ Abrams who keeps things close to his chest. One of the few tidbits that has leaked about the next Star Wars movie, Rogue One, is that there will be a few appearances by characters that we are familiar with. So far (March 14, 2016), the cast is named, but the characters aren’t.