Thank you for the feedback, Kiki. These are all great issues, and I will address all of them in a revised version of this.
I was planning to do #3 in the paper itself, and thought I did enough of an overview of it for the proposal (but perhaps not). I will certainly spend more time with it and will situate it within the literature.
Regarding the other 3 points, they are exactly items that were floating around in my mind which evidently did not make it into the proposal itself. I will address them all.