On your point Four, Bartomeu might want the moon, the planets and all the stars in the heavens for Messi, but who is going to give it to him?
Answer: No one
You cannot demand a price that no one will pay. Unless, of course, that's your intention, you don't want anyone to pay it.
If I'm reading you correctly you're saying this isn't a commercial problem it's a political one.
If everything is designed to ensure Bartomeu's continued dominance either directly or by proxy, then that has to be hammered out between Messi and Bartomeu and if the rumours are true that Messi isn't picking up the phone, then talk of potential swap deals and gazilions are immaterial.
We'll be alright, if Bartomeu does not craft a deal acceptable to City, then we'll walk, we'll be fine, but will he?