I think the font name and file name are the exact same, but just to be sure it's the font name.
I've...sort of made progress? The script was designed for touch screen menus, and I asked CNG about it and he wasn't really sure either. I'll keep messing with it and see if I can get it working though. The only issue is getting it to use map coordinates instead of screen coordinates. Of course, there's a possible workaround, but it wouldn't be very...good? You could make the sign event turn on a switch (or use variables) depending on the player's location, and use that to figure out what the screen coordinates of the event would be, but it would get messy.
What I did was search through all script sections for the world Arial (or arial black or something) and replace it with the name of the font you want. I had to do that for one of my old kits since Essentials wouldn't recognize the RSE fonts even after installing them (I even tried manually).
That's weird. I tried finding where parallel processes were handled, but I could only find them under common events, which isn't particularly useful. I wish Poccil would have left the default RMXP comments in.