There is one part I disagree with. I find no evidence supporting your statement that Meteor was the vessel that Jenova originally rode throughout the cosmos. Meteor could have just been a small planet/large asteroid that was within range of the Black Materia's magic.

It is the Ultimate Destructive Magic; it calls to planets [-- meaning
meteor-like rocks --] drifting in outer space and pulls them down to the
Planet.
That was stated in the Ultimania guide, but it was also almost word for word a line from the game (though I can't remember where in the game it was, I know it was there. I'll have to replay sometime). Thus, it's target could be any asteroid within range of its magic, so why do you conclude that Meteor had to be the vessel Jenova first rode among the stars? That vessel could have crashed into Gaia and been completely destroyed.

Except for that, it's a wonderful explanation.