Identify if an iOS In-App Purchase is a consumable or non-consumable?
If an item can be used once and then is not available again, it is a consumable.

If an item can be reused over and over, it's a non-consumable.

This is explained in the developer Apple's IAP overview you referenced:


  Consumable
  
  Users can purchase different types of consumables, such as lives or gems in a game, to further their progress through an app. Consumable in-app purchases are used once, are depleted, and can be purchased again.
  
  Non-Consumable
  
  Users can purchase non-consumable, premium features within an app. Non-consumables are purchased once and do not expire, such as additional filters in a photo app. Apple can host content associated with your non-consumable in-app purchases.


Based on your comments, I would say you have a Consumable IAP.  You app could be reject for other reasons, though, so this is no guarantee that it will pass App Review.