I'm more interested in the "TV Series" that is slated for August. I don't think it's referring to Rebels since that is referenced elsewhere.
Boba in Rogue One? I don't see why not. A fleet of Firespray-class ships? That would be cool too. A placeholder until they can show us what's really slated for fall? Most likely. Isn't a new Slave I lego set coming out in spring already?