Our approach to this has been a wizard as a push primer, shown the first time a user opens the app. The wizard talks the user through the permissions requested and explains why they are needed, and then on a button press we call the native iOS permission request. Otherwise, we rely on the users to navigate to the iOS settings themselves if they want to make changes, but we felt that this is how iOS is intended to be used. Seems to work well so far. If the user declines, that's fine and we don't ask again. Same for location as push.
