fps4pack should work fine for the DLCs too. You will need to enter 'cdlc' as file signature when repacking. You can also edit the text files (usually File 0004) with SCSEdit 1.5, just select Japanese when you open the file.
Here is a small update for toxpack that will make it a bit more usable.
You no longer need to make directories manually
You can now simply drag the file you want to extract to fps4pack and it will be extracted to a folder next to the file
I would like to express my thanks to everyone who has made this DLC possible for Tales of Graces F. Myself and many others have been waiting for this for a long time.
There is a problem with Richard's Code Geass Zero costume being unavailable from the title menu. It appears on the item list of the DLC menu but appears greyed out. I am currently using the USA version of Tales of Graces F.