Brady will accept nothing less than a complete reversal of the suspension, I would bet the ranch on that. With Kessler calling the shots, I think the league will quickly cave given they have no proof of anything.
Kraft's case is more nuanced. He's furious on a personal level at Goodell, this is not the usual "it's just business" disagreement. He left his dying wife several times to save the union agreement, was the only voice supporting Goodell last year, and this is how he's repaid?? And the other owners not standing up for him either? His usual accommodating manner is history now, he's in a Godfather mindset.
If his people convince him that suing the league could cost him too much, he may back off, but I think only if the penalty is reduced - say a small fine and low round choice. If they don't negotiate with him, then I could see him and Jonathan going Al Davis on the whole bunch of them.