Hey Steven,
from my side all that I've said was after spending like 13 minutes of thinking about the problem ;). So probably doesn't worth even considering.
Besides from that I also said that I've already implemented JSON API compliance but in an extremely hacky way just as a PoC.
So I don't really have answers for all your questions until I have time to sit down and think about the problem not easy for me to do that in a couple of minutes ;).
A collaborative list of things needed to accomplish for JSON API compliance is extremely welcome, you can start a gist if you want and share it here. I will include that at some point in the Roadmap
https://www.pivotaltracker.com/s/projects/978898
Thanks and happy new year!