Also, how does a phone on the Edge program work if I want to transfer it and the number to a different carrier?
An Edge device must be paid for before you can transfer it to another carrier. The phone is Verizon's until it is paid off. It can be blacklisted, and all carriers check that status before allowing an off-network/carrier phone to be activated. It is possible to have a balance and port to a new carrier, however, it is ultimately up to the new carrier as to whether they allow a phone from elsewhere on their network, as well as take on a new customer who has yet to fulfill their prior obligation to another carrier. Usually, this is where deposits can be affected.