The issue of the Win10 M+ desktop app v3.0.1 access to Contacts has been solved for me. I did some research on updating contacts on Windows 10 and found that the default People app on Win10 needed a new account pointing to my Google mail account. I'm not sure exactly why, but after adding this new account and restarting Message+, the desktop app no longer shows ONLY numbers, but now my contact names. Woohoo! It still doesn't show the contact pictures as shown on my phone AND in the Win10 People app, but what the heck. That's another problem for another day.