Luckily there was a Thailand guy that had cracked all the DLCs and kind enough to share it with the rest of the world. Follow the instructions below to download the DLCs at zero $!
1. Grab the link here: http://www.putlocker.com/file/5D88BBF3D2E5B1F5
2. SSH into your iOS devices and find the folder for the game under the /private/var/mobile/Applications directory.
* Since the folders are named using a unique ID such as 0BE5D130-0EDF-4A42-B287-3BAD56C7575B, you might find it difficult to find the correct folder. You can do this in either the quick or slow way.
Slow way: Open each of the folder until you see tffencore.app.
Quick way: Removing the game from your device and then re-intall it. After that sort the folders by Date. The folder for the game should now be located at the top.
3. After pinpointing the folder, copy all the files from the downloaded archive into each of the directory.
4. Make sure that you change the group owner to mobile instead of root after copying for all of the folders copied. This is to make sure that your game progress will be saved when you exit the game.
Q&AWhy my game progress for Final Fantasy Theatrhythm did not save whenever I quit the game?
It is because you haven't set the correct group owner for the DLCs files. Follow step 4 to solve this problem.