Ahem...Actually, the (for the moment) end of the mod is 2557, because Mantle's Approach. So if they could stretch shields over a three mile long warship, I'm sure they can do it on a space station that's maybe 600x600 meters. I like the one guy who drew it's interpretation (I would know your name if you posted more...) Station research NEEDS to be in the defensive tree, offensive upgrading already takes 40-ish minutes overall. Other than that your points are mostly fine. Hangars should be same as vanilla. Construction pods should start with 2 pods but at 0% speed, (they can be ship breaking yards) and gradually upgrade.
Just my opinion.
Technically the mod is build-your-own-canon, starting before the fall of Reach and into the "future"
[/major nitpick]
Looks awesome by the way, although I don't think the upgrade path will be linear (IE you can either get defenses or shipyards or [insert other upgrades here] first - none of them are (can?) be prereqs for each other)