Zenith:
Medal of Peace is in IW graveyard. Since it's big secret, I can't tell more. And if I can't tell more, I hide the fact that I don't really remember it, either.
To get L4 sword... go to northeast main overworld. I can't tell more. Altough if I remember, you have the requirements. But that sword can alter the ending... it's not a bad thing to see the neutral ending first then the best later...
Zorlaf:
You can't get that key yet. Seems like I forgot that there are just 7 that you need to get first, the 8th (what you see there) comes later. Otherwise it's not hard to get those 7 keys, just walk around the very edge.
TheOnlyOne:
You can tell which ending you got if you PM me with its details. According to what you found, you couldn't get the bad ending (unless there's bug). So PM me with what bosses you fought and what happened with "Knil", "Myra" and "those others"?

DFW:
Thank you! My life eventually really proved to be meaningful.
EDIT: Hm, I have 14 "5 star"s, while you have about 33 "5 star"s and one "3 star". Then I guess LI is still higher ranked...
Silly Cat 2:
Slash a part of the tall grass, you reveal ocarina sign, blow ocarina on that point. You need Goron Mask just a bit later. Next wallet is in dungeon. Bring superbomb.