I’ve gone ahead and implemented the “key claim URL” featured I previously mentioned. Everything I mentioned about email approval remains the same, but this functionality should hopefully give creators some more control over distribution without having to wait for authorization. I’m assuming Kickstarter gives a mechanism to notify backers, so you would just need to paste that single link into your message within Kickstarter.
I created a post here describing how it works: https://itch.io/t/2881049/new-key-distribution-method-for-kickstarter-indiegogo-and-csv-imports
I’ve also updated all the relevant documentation and UI to mention this new feature.