So for the add-ons. everything that is mentioned is available now cept for the drizzz, which will be available after the 17,500 stretch goal is made. With add-ons you can just add the amount to your total, and then just make a note when you do. My understanding is that you can not purchase more than one reward, otehrwise i would just make the add-ons in the reward section. Hope this helps a bit.