Hey! How about that? A simple suggestion (go back to static publishing instead of trying dynamic) proved to be the answer. I really should have thought of it myself, but I was so intent on making it work the one way I wanted.
So, you can now access my blog at www.dianaschnuth.net or blog.dianaschnuth.com — they both point to the exact same place. Comments work again, feeds should no longer do funky things, and all is well.
I can now go back to posting normal blog entries and waiting with bated breath for my regulars to post comments. Oh, yes, and I can also go back to finishing my website redesign.