When using React Native (and also storing your network in JS) you can choose to push updates and fixes to JS part of your code without going through store again.
Yup that's basically it. The hack was just in getting Tensorflow to accept/load its neural network definition from the JS bundle (what CodePush distributes for you) rather than from the main Cocoa bundle.
Just as a note, people/developers have had messages from Apple telling them that they need to remove code which allows them to update their app outside of the app update/review process.
Really cool stuff! I didn't even realise you've switched jobs, but that explains why I didn't see you when we popped in at Townsend the other day! Keep up the good work.