From what I’ve read and heard, legendaries will be done via raid-like events, similar to the Mewtwo ‘event’ in the original trailer. I also heard something along the lines of the bird trio event being team-oriented, so perhaps our Mystic/Valor/Instinct choice could have a big bearing on whether or not we get them (or…

The issue with the ‘sending a message’ idea, though, is that other players can’t see the nicknames of your pokes. So you don’t really get the intended message across.