I love the idea of a "deckbuilding" city sim instead of an expansionist framework. I think that's hitting all the right notes of getting players to reconsider which societal practices can continue in a greener world, which must be heavily modified, and which must be abandoned altogether. Your timeline for production is also looking strong and clear.
I wasn't sure if all the stuff at the end of the document was brainstorming from each individual team member, but one of the challenges the jam might present for a team this size is coming together around a cohesive vision. For individual team members, that might mean giving up a couple of pet features that would be "nice-to-haves" in order to land on a really polished core experience. Loving what I'm seeing so far, and excited to play this one a couple weeks down the road! :)
Thanks for participating in the jam, and for getting off to such a great start!