So you'll be happy to know that "Chaudown" unlocked for me with no issue today after I used the 5th character's striker. So you can update your guide with testimony that the best way to go is to use each character's striker BEFORE beating the game (And make sure to unlock & use the Mr./Mrs. Chau prior to beating the game with anybody)
Yeah, I dunno what happened that they can't get the bats going this week. Thankfully the Sox are choking against Baltimore. Have fun at Target Field. That place is AWESOME! I'm bummed i didn't get out there more.