Rock,
In many ways your post makes a LOT of sense, but there is one reason I don’t think it will happen.
The only issue, that I’ve heard, with AD are his 2 holdouts. He is a top player, possibly all-time great. He is a hard worker, and has been money when we needed some coin! I never heard a bad word about him, again outside of his contract dispute.
My point being, is what message is the FO sending to the players, none of them as good as AD, by shipping their best player to another team. McVay, from everything I see/hear, is almost thee anti-Belicheck. I think the FO is sincere in trying to sign him long term.
Having said this, your scanario is an option.
Clear as mud??
BeachBoy