Well, after seeing someone else report being successful I decided to take another crack at it and was finally able to add my Cap1 cards to Google Wallet while outside the US. Here is what I had to do:

1) Enable developer options on my Android
2) Download a Mock GPS app (I used "GPS Emulator" from the Play Store)
3) Enable GPS Emulator as a designated "Mock GPS" app in the Android Developer options
4) Enable a VPN app with a US IP address (a regular commercial VPN worked for me)
5) Pick a US location with GPS Emulator
6) Match the phone's timezone to US location selected
7) Disable all SIMs (not sure if this is necessary...)
8: Clear Capital One app cache

Then I proceeded as normal (entered card details into Google Wallet, then was asked to verify in app, Cap1 app launched, asked for 2FA and then let me verify without the "we've run into a snag" message). As mentioned, you will need some way to satisfy the 2 factor authentication - I was able to either tap one of my physical cards or receive an SMS.