"Who should have but didn't?" is an odd question because they are gone; Beasley, Brown and McKenzie.
Kincaid isnt guaranteed to start, or to necessarily replace all their targets and receptions.
I see him as a backup TE, an occasional TE 2 in some sets, but not the regular starting "slot receiver." I think Bills will move him to r
create mismatches but he won't play every down and his usage could vary by opponent.
Hard to predict stats but I hope he has quality production as needed.