Okay, the PHP issue is past. But then I was modifying the httpd-vhosts.conf file, and suddenly Apache shit all over the rug and started complaining that it couldn't find the PHP module. So I had to start over again. This time, I found a method that allowed me to install Apache 2.2.14 right over top of the built-in 2.0.x version. Then I built the PHP, and verified that it was working. But then when I went to check my phpinfo() in the browser (Firefox), it clearly wasn't working at all. After some testing, I found the issue, and started over AGAIN. The browser, though, stayed open, because I was working on something else (my online job). After finally rebuilding Apache and PHP, things seemed okay, and the server restarted without issue, and the virtual hosts were working just fine, but phpinfo() still wasn't working. Man, I wracked my brain and kicked my computer and studied for hours about mime types and verified ten times over that everything was installed right. Then on a whim, I decided to check it in Safari. Worked right away, no issues. After restarting Firefox, it worked right as well.
I guess this is normal behavior - the content of the webroot folder had not changed even by a byte, so a refresh had no effect. For future reference, how can you force the browser to renegotiate with the host so that server function changes have an effect? Surely it's not necessary to reboot the browser everytime I make development changes?