Sal wasn't the leaker. He just delivered the message.
I swear everyone is being a Leonidas toward him.

You ever hear of the term "Don't shoot the messenger"?

I have a theory: The person who leaked the information to Sal Romano had outdated information, which is what people have been saying the whole time. This explains "Pokemon from X/Y". What I'm getting at is this: Chrom may have initially been the decided playable character, but for reasons unknown(Maybe more diversity in the roster?), was changed to Lucina. This could also explain how Robin and Rosalina were not predicted, they may not have been fully decided when the leaker got his information. This might also mean that Lucina could have been in Robin's FS instead of Chrom.