Anybody who pre-ordered ARR, doesn't matter what version (normal or Digital CE) will get: Cait Sith pet and Mog Hat AND be able to play these few (Friday is when it started?) days before ACTUAL launch for free.
Come Tuesday is when you will have to register your game. I will get an email from Amazon for my keys..
You will also need to create a payment plan.
Once you do this, from my understandings, you will get 30days for free.
Once the game has been register is when you will get your pre-order items. If you bought a Digital CE (or physical), you will be able to claim them on Tuesday as well. ATM No one has any of the perks from pre-order other than being in Early Access.