A:AnswerYes,
I was able to transfer my number to the new sim card, and my old pay-as-you go account was transferred as well. Easiest way is to talk or chat with a customer service rep.
A:AnswerThere are several at amazon, most are the rugged type and they're all under $10. I got the innova smart grid defender and I'm really happy, it feels much more solid in my hand now than the phone by itself.
A:AnswerYes, this phone will have MUCH better coverage as long as you have band 12 LTE in your area. Google 'T-Mobile band 12 map' and youll be able to see.