I had my GV number forwarding to my regular number at first, so when someone called me both Hangouts and the standard phone app would ring. I turned off forwarding and now making and receiving calls from my regular number and GV number separately seems to be working fine. SMS also seems to work fine.
The only problem is that once I turned off forwarding, my regular number went back to the standard voicemail service. What I'd like to happen next, which I'm not sure is possible, is to still have my regular number use GV as voicemail. Is this possible? Has anyone managed to do this?