Does anyone know will Amazon charge me the new lower price when they process the order or do I need to cancel the order and reorder it with the new price?
I wouldn't assume even if someone claims Amazon did it for them. Contact Amazon and ask.
I think trying out a different phone / OS is a fine thing to do. Just hedge your bets and keep a back-out plan ready. You might love it or you might prefer to go back to what you had before.