Questions about AT&T contract type, and canceling preorder

[swamyg1]

I ordered 2 phones through the Apple Store App:

• iPhone 128gb 6 Plus with a 2 year agreement for $399 (Oct 13th to 20th delivery)
• iPhone 128gb 6 with 2 year agreement for $649 (can pick up on 9/19)

- The 6+ was added to an AT&T account with expired contract.
- The 6 was added to an account with 1 year left on the agreement.

I want to cancel one of the phones I ordered, because I haven't decided which is the right phone for me! I have a few questions:

1. Unfortunately, I did not look as much into Next as I should have. I used this calculator today and realized Next is a better value for me http://attcalc.com/next/#calculate. Am I able to change over to Next?
   
2. If I decide to keep the iPhone 6, am I able to swap contracts or change the contract type to Next so it's on the line with the expired contract?
   
3. Can I pick up both phones at the apple store, try them out, and return and cancel the new contract on the phone I don't want (within 14 days)?
   
4. When is it too late to cancel online orders? I'm considering camping out on launch day but I would need to cancel at least one of preorders if I'm able to get a phone at the store.

I feel like I might be better off just canceling both orders and camping out? I would have made several threads but I thought that would be annoying for you guys! Thanks for the help!

 

[tangfish]

I'd love to know how to cancel my order on att.com too. Seems to just lead you in an infinite loop.