The Moto G does Skype/Hangouts/etc like any Android phone does.
It won't support (as far as I know) any of the carrier implementations of WiFi Calling, where you can seamlessly use your carrier phone number on WiFi. That is generally enabled by the carrier on newer phones.
But the other stuff should work fine. I have used the above services and others on my Moto G 1st Gen (VZW)...