Have you tried it yet? Do you know if calls will transfer back to cellular when you move out of Wi-Fi range? I was impressed with how well it worked on Republic Wireless.
As long as you have an LTE signal it transfer seamlessly from wifi to VoLTE. If you have no LTE signal or you turned off LTE Voice and Data, I think it will drop - I haven't tried that, but that is my understanding.
Can I ask where you got the list of supported devices? I've been waiting months for iOS 9.3 to come out so that I'd finally have wi-fi calling on Verizon for my 5S. If it's not supported I am going to be a very unhappy camper.
You need to have HD Voice active on your phone and account for wifi calling to be allowed (This turns on Voice over LTE or VoLTE), and that is only available for the Apple devices I listed above. Unfortunately, the 5S is not supported.
To be eligible for Wi-Fi Calling, you need to:
Note: If you have any features that are incompatible with HD Voice, you'll need to remove them before you add the HD Voice feature to your account. Find out about which features are not compatible with HD Voice. To learn more about HD Voice, the capable devices and how to activate it please visit: www.verizonwireless.com/advancedcalling
Sorry, I have no info if or when this will be on prepaid. Verizon has always kept key differences between prepaid and postpaid to keep postpaid the "premium" service.