A thought:
Meis said on Twitter the Etihad solution wasn't ideal as it affected schedules. Because of that people (including me) have assumed building one end after the Games is a no-go.
But, maybe the problem he sees isn't that they built one stand after the Games, but that they had to dig down to make it work for football, meaning it couldn't be used for football until a year after the Commonwealth Games.
Wouldn't it be possible for the club to move into a three quarters completed stadium in 2021 (still a larger capacity than Goodison), lay a platform track inside it after that season and remove it before the 2022/23 season (as promised in the Mayor's letter) and build the final stand during that season with the stadium still in use.
That solution would get around the geometry of fitting a track into an "ideal" football stadium, would mean Everton could move into the stadium before the Games and use it the season afterwards unlike City, and it's consistent with everything the Mayor and Meis has said.