You can go back anytime by showing the tri pass or rainbow pass to the sailor at the harbor in vermilion city he's the same sailor who let you on the SS Anne.
yes you can in fact if you reach the seventh island the team and level of the elite four and your rival will change.
a valley on six island
island 4
About 2
you have to donelode it on to your gamboy.
Yes.
Cinnibar Island.
two island, but after a little while.
You can double your Pokemon in fire red by putting them with a ditto on 4 island.
There is no 8island on fire red sorry.
you have to go to 4 island NOT
use cut