Giant Green ChuChu
A simple boss. Just use the Gust Jar on his tentacle leg-supports (they turn red when you use the gust jar upon them) until he makes a sound and starts teetering. Stand to his side, then when he falls get out of the way and then slash him like mad. The Giant ChuChu will jump and teeter this way and that, and this jumping increases as it loses more and more health - peaking just before you've killed him.
Gleerok
Get to his side and use the Cane of Pacci on his shell. Then climb his neck and slash his body till he starts going into the lava. If you get low on health, use your sword on the flames he spits out for hearts.
Giant Blue ChuChu
Weak: Gust Jar
Mazaal
Weak: Arrows in Hands/Pillars inside
Giant Octorok
Weak: Lantern
Gyorg
Weak: Roc's Cape + Duplication
Vaati 1
Weak: The eye on his body
Vaati 2
Weak: Duplication + Sword
Vaati 3
Weak: Cane of Pacci, Sword