Contact the app developer to verify that *everything* is backed up with an iTunes backup. I don't believe Minecraft uses cloud saves either for backups. That being said, I really don't remember if the Minecraft app data is *fully* backed up with an iTunes *should* be but you take your chances. Restoring the device would not restore certain app data for certain apps which is why these 3rd party apps were used. Yes, since iOS 8.3, Apple has blocked access for 3rd party apps on the Mac and PC to access certain parts of the iOS file system which is/was how some users (like myself) were backing up app data since backing up through iTunes does not backup certain app data for some apps.
