How did you get this through App Store review? My understanding is Apple tends to be pretty strict about apps that rely on reverse-engineered private APIs.
App Review didn't object to that. There are various apps on the App Store today that rely on reverse engineering, such as unified messaging apps, alternative rideshare price comparison apps, and driver-side rideshare aggregators.
App Store review is really just luck of the draw in my experience. There is usually no rhyme or reason to a decision, changing some minor thing and re-applying works a lot of the time.