Audition CC, Focusrite 2i2 and podcasting via computer phone?

I am using Audition CC with a Focusrite 2i2 to record podcasts via phone interviews done through my computer (Skype and Google Voice). The attached image shows how my computer, microphone and the 2i2 are connected. Also attached are screen grabs of my Audition CC device, Host, and Interview settings. In short:

• Device input: 2i2 USB
• Device output: Built-in
• Host track input: 2i2 line 1
• Interview track input: 2i2 line 2

The problem I have is that when I arm the Interview track to record (before initiating phone call), I instantly get "noise" on the Interview track, and when I do initiate a call, I get an echo from the person with whom I am speaking.

Further, when I speak into the microphone, the line 2 monitor light on the 2i2 activates, but not the line 2 (microphone light). And, although I can record into Audition via the microphone, Audition does generates flat-line voice activity on the Host track.

I must be making a very basic error somewhere in my configuration. I just cannot figure out what it is. Any advice would be appreciated.

I am using a MacBook Pro with OS 10.12.6.