I don't think the coaching staff/FO will be judged on the record this year, maybe even next. If Kraft just mindlessly wanted to go back to the playoffs they wouldn't have $50M cap space left. I think the key for them is selling Kraft that the team is progressing.
I think what gets them fired quick would be if they go 4-13 again or something like that, but no one is developing. Like on the OL, if it ends up being Okorafor/Sow/Andrews/Leverett/Onwenu and Wallace/Robinson/Strange all look lost and it feels like a jumbled mess going forward. And at WR if none of the young guys really play well and it's Bourne/Osborn dominating the snap counts and leaving us feeling like we're still close to starting over at WR next year. And of course if Maye plays poorly if they throw him out there and looks lost and/or earns bad practice reviews. So on and so forth.
Heck, even if a bunch of the vets play well like I mentioned where Brissett has one of those random good bridge QB years, Bourne/Osborn play solid at WR, and 1 year vet signings Okorafor/Leverett stabilize the OL and they squeak out 7 wins, I think Kraft grades that more negatively than if they go 4-13 with a lot of young player progress.