I freaked-out last night and did a reinstall and closely followed all instructions on this site and http://www.devlounge.net/articles/the-ultimate-bbpress-guide/. I believe most of my frustration has been caused by an ever-shifting hosting environment during this project. The domain has now resolved and everything is working nicely again (after re-install).
About those header errors: I did find whitespace at the end of wp_config.php. Those few invisible spaces kill me every time.
Now, on to outstanding misc. CSS issues…
Thanks for the help.