I would hope there was a way to make M.L. happy without throwing the team salary cap structure out the window and without encouraging other players to follow suit themselves a could of years in to their new contracts.
You don't have to worry about Pete and John doing anything that's going to severely handicap their ability to resign Russell Wilson and leave a little spare change for contingencies. They'll let ML walk before they do that. They've already shown their hand in that regard with Bevell's "running back by committee" remark. There's the possibility that Bevell was conscious of ML's unhappiness and was giving ML a 'shot across the bow' with that statement.
As for your concern about setting a precedent for other players to follow, the precedent has already been set, and not necessarily by the Hawks. It's not uncommon for a player that feels he's being underpaid to renegotiate a contract, and whether or not the Seahawks renegotiate Lynch's is not going to have any impact on future Hawks one way or the other. Players are driven by their agents, and the agents know what the Hawks can and can't do.