Using Project Fi with a Nexus 6P, and wifi calling and texting works just fine.
As far as Verizon goes, I gave up on them as well. I won't have a Samsung phone, and their first release of wifi calling was on new Samsung phones. Wifi calling will be enabled by iOS 9.3 on Verizon (iPhone 6/6s) as well, but that's just not good enough. I decided some time ago that Verizon was too expensive for me, so have been looking for alternatives for some time. Since I live in a fringe area for Verizon, etc., wifi calling (or a femtocell) is a must. Found Project Fi, has great wifi functionality, and the Nexus 6P is a great phone. Decided that was just perfect for me, and is much less expensive going forward. Working quite well.
And, surprisingly to me, Sprint has turned out to be the strongest cellular provider in my area. Didn't expect that one *smile*.