I cannot answer the last part, but I can tell you that FOBS-R is not made with TKool anymore. Zell shifted to PixelGameMaker since the scope of what they wanted FOBS to be was too big to fit within it. (And I assume making a FOBS Part C would have been very annoying.)
Oh great, an easier to work with engine ! Do you have tools to decrypt and unpack PGM ? If not, I still have something around that worked pretty good so far for every pgm gamed I tested. It's a bit cheap and dirty because I needed it to do the job for me, but it works. Assets, audio and project json recovery aren't an issue, the big problem with PGM is cocos. When they use japanese character in path the asset won't load on Linux. It's very annoying. At some point I should make something to auto fix and translate PGM games on Linux, but I've so many things to do...Also you need PGM engine or be very patient if you wish to mod the project as it's everything in one big file.
I don't have the tools for what you need, unfortunately, and I have no idea if modding on this engine is well established. I'll see what I can find for you when I have the chance, but modding is not my realm of expertise whatsoever. There might be someone in this thread that's more equipped to help out, but I'm not sure.
Extract on the save folder (game folder > resources >save)
Byakko's arena has three colored pillars that match the ones you see when you get to the ruins. Memorize their colors and how said colors are arranged. The pillars that match those three pillars will lead you straight to the ruins.
It's constant, but there's no point in telling someone the answer without telling them how to get to that conclusion. With this solution, while it may take longer, knowing stuff may be structured like that later makes it less likely they'll need the help later.
