Depends on which game and your point of view.
Personally, my favorite boss is Eox in Phantom Hourglass
He is the final boss.
sure
in the tree
the dog
you have to blow to enter and for boss you have to get boss key
a fourth monkey, and the mini boss. then more monkeys and the boss.
in hyrule castle
Eox the stone warrior
Ganondorf. you might think Zant, but he is not the final boss.
Its easy really. just do what Zelda and anjean tell you to do and shoot the last boss with light arrows. last boss sucks.
You need to be more specific about what mini-boss and what Zelda game. However, there is a mini-boss within each dungeon, providing a useful item after defeat. I would recommend using walkthroughs for more details.
by using the spinner