Update:
Recently finished the quest, and am still unable to do the diadira quest. chose to redownload the game and transfer my save files, but unless it's the saves that are shot, I still can't get in. Maybe another of my quests are stopping me from getting diadira or something? trying other methods
Signed, An Idiot w/ no Melody
Edit: only other quests I have are as follows
Stuck in the Middle With You
Rescue Me (The Diadira Quest, so duh)
You Get What You Give
(Character Name) Baker and the Philosopher's Stone
Going to try and do the quests and see if one is blocking me. If not, will restart and use Loan Money to attemt the diadira quest, if I can that early at least