The cook quest has all of its ingredients in town, though, not necessarily in the same world. Just talk to people and you'll find them.
The band member you can't get til later, don't worry about it early on.
I've already beat the game, mind telling me where he is so i can finish that quest?
The band member is in the main town with the other band members in a house at the bottom. You need to break through a blue wall to get to him.
The cheese is from some guy on the right-ish side of town I forget specifically which person, seems like it was a squat fellow. The quest then goes on to need beans from a lady to the left a bit from the kitchen, chiles from a dead guy on a platform on the stairs leading from the lower level and tortillas from a lady to the right of the kitchen a bit. If you can't find them, I'm sure there's guides on google by now.