You said "make or beak." To me that means whose performance is most crucial to the success of the team--the ones who, if they play badly or well, have a disproportionate effect on the record. And "make or break" means that their ability to play at a high level is under question.
So, given that, the answer is:
1-7 Fitz
If Fitz plays the way he did in the second half of the season, then the team will be hard pressed to win even half of their games. After Fitz come whoever's playing left tackle, whoever's playing #2 receiver, and whoever's playing linebacker. And Gailey, who is definitely on the hot seat.