Update on Verizon: Wifi calling is available as of the 9.3 iOS update.
Settings->Phone->Wi-Fi Calling
http://www.wirelessweek.com/news/2016/03/verizon-expands-wi-fi-calling-iphone-ios-93-upgrade
A quick follow up: VoLTE must be enable as a (no cost) service. If it's not done at purchase you can add it through your account online.
Then, you have to turn it on in the iPhone settings, to have Voice and Data.
A third question, different VZW issue: Is tethering now a standard feature (as with AT&T)? It doesn't require an additional plan, just turn on the iPhone feature?
Quick pair of questions:
Does simultaneous voice and data on a Verizon iPhone only work when you're on their LTE (VoLTE) network?
How common is it to drop down to 3G or 4G (or whatever VZW has) and lose that feature in major cities (L.A., D.C., NYC)?
Thanks. :)