Quan's Dwelling is a cave to the east of Treno; you can reach it on Disc 2, but you won't be able to do anything short of looting some of the more basic treasures. To really accomplish anything, you'll have to return on Disc 3 or 4 with both VIVI and Quina in your party. (You won't be able to do this until you get the boat.)

I see dead food

   Grab the Ether from the chest in the lower-right, then walk behind the sand waterfall in the background. (Don't worry, there aren't any enemies in here.) Hit the Circle button to climb down the rope. A second Ether lies in the chest in the bottom, and the Scorpio Zodiac Coin can be found by searching the south wall. You can also touch the steam to restore your HP and MP.

Quen Family Reunion '00

   Head through the doorway in the upper-right. If you've got Quina in your party, his theme music will start playing, and he'll start hallucinating about food. A weird sequence involving Quina, Quan, and Queru follows. After Quan vanishes, you regain control of Zidane. Check the clock on this screen for Hermes' Shoes (no, not an Elixir!), then go back into the library where Quina was having visions. Climb up the ladder on the left and activat the exclamation mark for a third elixir.

   If you've got a Sea or Sky Chocobo, there's one more secret you can find here. Search the bucket at the bottom of the back porch; if you've got a Red Pepper, a menu will pop up. Choose the top option and you'll end up on the world map, standing on the ledge. Hit Triangle and use a Red Pepper to dive into the ocean and collect a hidden treasure trove yielding 15 Topazes, the strongest Racket, and the Red Rose Card.