YES YES YES! Thank you so much for your help, everyone. Whoever suggested the link http://ffmpeg.zeranoe.com/builds/
Gave me everything I needed. I had made a lot of small adjustments prior, like changing stuff in the pms.bat[?] file under the "supported audio formats" section, but none of them fixed the problem. Whether they impacted my success or not I do not know, but I downloaded the 64-bit version from the link provided and swapped in ONLY the ffmpeg.exe file into the same subfolder within my PMS directory, renaming the OLD ffmpeg.exe for backup, and VIOLA. ALL of my flac files are showing up, even my 24-bit files. This had been bothering me for days, seriously, thanks everyone.
If any DEVS read this thread, please don't make the future releases easier for flac playback!
PS: The only quality downgrading occurring is with the resampling to 48/44.1 - tried listening to 15 Step - Radiohead at 96kHz, and it sounded bizarre.