Ultimately it comes down to converting the contents of a PC package file into the XBox FB format so the console can read it.
On Xbox (XML1/2/MUA) your characters are all located in the directory "assetsfb\packages\generated\characters\" inside the assetsfb.wad which can be opened by renaming it assetsfb.zip and unzipping it. The XBox reads zip files- so once you edit something within the directory and rezip it you don't have to bother changing it back to .wad though It would really be helpful if it just read the unzipped files in the first place since they do not have to be recompressed in order for the Xbox to recognize them.
The Modding Rundown: FBs tutorial is extremely useful- though at first you may not completely understand it until you actually open an FB up.
The biggest thing to remember is that IT IS IMPOSSIBLE to get around changing the four bytes that indicate the size of the files within the FB if you want your game to function correctly. Not doing so results in all files following the point where you have added or subtracted information not being rendered correctly in game. This sounds terrible, I know- but can be fixed by very simply entering the correct filesize using the formula provided in the FB tutorial.
Still, always backup your files.
Once you understand how to add/remove information within an FB you can compare the contents of say blade_0101.fb and blade_0101_nc.fb (Xbox-MUA) with thier PC counterparts and find out where things should go.
