Hi Ben,
To keep tabs on emails that are going out, I've used the "Send Alert" function. I just add that to the flow step, in addition to sending the email, and set it to go to me. It's kind of like BCC'ing myself.
This way, I see the exact email, what AE it came from, who it went to and what it said.
I think my situation, while very different, has some similarities. The emails I'm keen on watching are being triggered from our proprietary call prospecting software via an API to Marketo. Coming through the API are the values that will fill the tokens in the email, primarily: Lead name, AE name and AE email.
I like to watch the emails coming through and spot check to make sure there is accuracy here as we have had a few bugs in the past.
While I would agree to test the emails with your HTML crew before hand, this may work to enable them to keep tabs on the emails as they go out. I know it's worked well that way for me!