You would hold the confirmatory vote before you do all of that. You'd go to the EU, agree what joining looks like, and before doing any of the actual implementation you hold the vote
Which is what would be right now? The final agreement is of course signed after all that restructuring took place.
No, you would sign the agreement before doing all the restructuring. Doing it first would be silly
Except that the EU wouldn't let that happen. You need to do the restructuring before you become an EU member, the other way around would be rather silly for the EU.
The joining process is already precisely defined.
Then what are the people voting to negotiate? They should just be presented with an in/out vote