The Persona games were derived off of the SMT3 engine, and many of their formats are similar or the same.. This is also the case for SMT3's font format, but there's sadly something throwing it off when trying to use this tool.
At a glance the header appears to be four bytes longer than later games, though I'm not sure why.. Also although your tool doesn't parse the file correctly, it does produce a misaligned image that vaguely resembles the font sheet. (You can make out the characters if you look closely enough.)
I'm not sure how difficult it would be for you to add support for this, but it would greatly help me in my translation efforts. Failing that though, I'd be grateful if you could at least point me in the right direction toward figuring it out for myself. Regardless I appreciate the time you've taken to hear me out, thank you.
Below I've included the NA and JP Fonts for SMT3, for reference.
font.zip
font-jp.zip