Swapping SIM cards?

Yes, you can do that without any hitch since the data plan costs are the same

 

Well the IMEI number will still be registered to the original phones, although to be honest I'm not exactly sure what that will do. It may cause problems with different serial numbers too if you ever have to send the phone in for warranty work.

 

But in what order do we switch SIM cards in relation to when we activate it through iTunes. I'm just scared once I activate the phone on my other family line's iTunes account it's going to sync with that. Will we need to call ATT to switch IMEI or should it do it automatically? Still a lot of unanswered questions I think....