I know that it would be out of character, but now I'm trying to make up a plan how this might work. If Mystery can counterspell, then if you send him along while disguised as someone else, it might be possible.
However, as you've said, it would not really accomplish much anyway and Konsi would never do it.
If the idea involves simply walking into Avernus, I'll be as impressed as I'll be amused.
Beyond that, did the party specifically leave some members behind when I did not notice, or are they simply offscreen during this comic?