Well, like I said, I took one of the keys from the Wicked Fortress back to the magic cave, thinking I had done the opposite earlier. (How did I get to the Wicked Fortress without first clearing the magic cave? Trial and error at the puzzle screen with the lake and the four hookshot targets 
)
The room in the middle of the map with the orange bit? Hmm, not sure what "orange bit" you're referring to, so I guess I'll have to go try that out... pretty sure I explored all the rooms, but I might have forgotten about that one and left it alone after I explored it... you do mean a room in the Wicked Fortress, though, right?
