I believe that Luke has actually been in the trailer all along. At 2:10, Luke starts talking; "The Force is strong in my family... My father has it (?????) I have it (He reaches out and touches R2). My sister has it. (YAY!) You have that power too." (who?) This is Grandmaster Jedi Luke Skywalker talking (Although that's only his title in the now-declared Legends.)
I haven't seen the movie, but I'm REALLY looking forward to watching it. Hopefully soon!