Sorry, but that's just way too technical, AR.
True, there is nothing formal for Brady to respond to. But so what? That doesn't prevent Goodell from feeling his interest out before making a formal offer.
If Kraft says to Brady (and substitute anyone else if you don't like the Kraft example), "Tom, there's no way that Goodell will reduce this if you are going to fight in Court after getting the reduction. He takes crap from the other owners for reducing it and then has to fight you? Not going to happen. But I am pretty sure that if you accepted a one game penalty, that Goodell would go to that and you could be done with this BS."
Yes, Tom can't formally respond to that but if Tom tells Kraft that he's interested, Kraft can relay that to the NFL/Goodell and then perhaps the offer gets made after the lawyers get involved.
Now I'm sure there is more to it than that. But I don't think that the process going along those lines is fantasy. I think that IF Goodell is of a mind to reduce the penalty, that he would want to proceed directionally in that way.
Again, it is quite possible that Goodell is dug in and will just uphold the 4 games. But if he wants to settle or at least try to do that, I think he does something like this as a first step.
There have been times in my practice when I have gone to opposing counsel with a comment along the lines of "I'm not going to even begin to proceed with negotiations unless something like X could be of interest." That could lead to a "yeah, something like that could work," at which point an offer might get made by my side. Or it may lead to a "no way. no how," which could in turn lead to no offer being made or my side to sweeten its opening bid. Or it's just information that gets factored in for a later negotiation. .
But this kind of pre-negotiation, meta negotiation talk is not remotely unheard of and the fact that there is no formal offer that could be accepted by Brady is a total red herring.
As to your second point, I don't know if you have the law right on that. I am hardly a labor lawyer. But if we assume you are right, I would assume there are work arounds and that Goodell's representative (Kraft or whoever else) could message that to someone broadly on Team Brady.