HELP - Routing for Zoom R 16 for Computer Podcast

[GV]

Hi,
I am being interviewed 'remotely' via Google Hangouts on a podcast, i.e., the host is contacting me through Google Hangouts and is interviewing me over the computer.

I am going to record audio independently on to my Zoom R 16, and send the host the audio file from the R 16 because it will be better quality than the safety recording the host is making of the audio coming from the Google Hangouts connection.

QUESTION
I had planned to use a headset mic. to listen to and speak to the host, while having an SM58 plugged into my Zoom as a standalone recorder, with me monitoring the audio signal on the Zoom visually.

HOWEVER, if I wanted to be able to monitor both audio signals (from Hangouts and the R 16), while recording on the R 16, is there a way I could do it (a) either with the R 16, or (b) using another audio interface as well as the R 16?

I am assuming that if I had another audio interface plugged into the computer, with a mic. going into it, and also came out of that and into the R 16 somehow, and then had my headphones plugged into the R 16, I would be able to do this, but I am stupid and confused, so would welcome some enlightenment about how to do this.

Thanks for any advice, suggestions.