2.) Any good tutorials on creating a proper zxp and then installing it? I can't find any, only ones on modifying existing manifests to work in other adobe apps or ones that involve full-blown interfaces?
Creating a proper ZXP: https://github.com/Adobe-CEP/Getting-Started-guides ...Photoshop notwithstanding, this process is still the same in other products that support ZXP, as well as Photoshop running in Intel mode.
Installing it? https://github.com/Adobe-CEP/Getting-Started-guides/tree/master/Package%20Distribute%20Install#installing-the-zxp-packaged-extension ... except Option 2 is now called "UPIA" and doesn't need to be downloaded: https://helpx.adobe.com/in/creative-cloud/help/working-from-the-command-line.html
I'd also add an option 4, "turn .zxp into .zip, unzip it, and put it into one of these folders": https://github.com/Adobe-CEP/CEP-Resources/blob/master/CEP_11.x/Documentation/CEP%2011.1%20HTML%20Extension%20Cookbook.md#extension-folders