Please use .png instead of .bmp when uploading unfinished sprites to the forum!
Opening FFT:C with TacText should make it completely editable. The problem is likely that we used a slightly modified version of TacText the fixed some bugs that aren't fixed in the current public version. I will talk to Melonhead about it.
Is the additional fight from the PSP version going to appear in FFT: C?The fight in Chapter 4, after you get Meliadoul on your team, where she is added to the battle as a guest and fight Kletian.It's been a while since I played the PSP version but I think there were a few more battles w/o new characters (other than the one in spoilers above) that did not have specific new content like jobs and/or items that possible could be added.
I think Raven's made some extra space for events, so that's something you might want to look into.