It seems I've been at the end of the rope for Find Mii II, as far as finding new items to unlock goes. Yet, my list of hidden unlockables is not nearly complete. I've been through Find Mii and Find Mii II multiple times. I even went back through Find Mii after a long time to see whether or not more unlockables would open up. There was nothing. I could retry the original Find Mii II. However, I've been doing the "Secret Quest" version all this time over and over again. It appears that the game has nothing left to offer.
Where do I go for unlockable items now? I've been stuck wearing the same Yoshi hat for weeks now. I'd like to try and see what all of the other hidden hats are to wear, but I don't know where they would be. Do you have to spend extra money on the other miscellaneous 3DS mini-games to access them?