You don't defeat knights, you talk to them and they'll give you a weapon to defeat a beast. (On the jungle planet, find the Laser Lance down in the plants before you meet Sir Cador.)
You do not get or use a bucket on Astro Knights Island.
There is no treasure chest on Astro Knights Island.
No. (see related question)
There are no bird eggs in astro knights island.
How do you talk to the girl in the hay loft at astro knights island?
its on the island
When you defeat Mordred, the game is over, and the Princess will kayo him for you. (see the related question)
On every island you have to be the one to save whatever needs saving. That includes the kingdom in Astro Knights Island.
use the rope and tjhe code dh h husfvbsufhsuiecdfhf
it is in the left
Astro Knights
With Mordred