Kroft's health may play a role in who they keep. If he's not ready for week 1, which I doubt, I see Kroft put on PUP or IR. The Bills go with 3 TE (Smith, Sweeney, and Knox) and 7 WR. Revisit everything when he comes back.
So 7 WR, 3TE, 2 QB, 9 OL, and 4 RB is my guess for offense.