First, thanks for your feedback, ideas and analysis.
The developers of the theme I use seem to be a theme-farm out of Asia. There have never been any updates. Other than this issue, the theme has worked beautifully for me, so I’d like not to change it.
I actually looked up Contact Form 7 a few days ago and liked what I saw. I wasn’t sure how to go about replacing the built-in elements, but I imagine it will turn out to be pretty easy.