Those don't have anything to do with KitKat. An upgrade to Lollipop will not improve the range of the WiFi radio and until Verizon updates VoLTE to do WiFi or CDMA handoff at the very least, and improves the LTE coverage area, that's not going to get any better, either. I get that it's important to you. You bought the wrong phone for what you need. But, we've had this discussion before, haven't we?
I definitely don't want to soft-pedal your issue with VoLTE, but it's not going to be fixed just with Lollipop (unless Verizon happens to coincidentally improve VoLTE at the same time.)