I am in the same boat. Hopping seems pointless with it being limited to after 2 and 6 PM closes, but if they extend the hours it may work out better. I didn't get hoppers though so I don't think I can upgrade my tickets until I am there (purchased seperately).
You should be able to add the hoppers through MDE! (Or over the phone if you don't mind the wait.) I am waiting to see if hours are extended for our trip, too. It definitely doesn't seem worth it if parks close early. But if we extend, I was planning to add the hoppers through the app to avoid waiting in line at the parks to do it.