[Script] Questions about Gym Leader rematches and other

So, I have a couple of questions.

1. I want to create a script that allows for gym leader rematches after beating the elite four, and after beating them the trainer is given an item.

2. I want to create a script for Hitmonlee and Hitmonchan that would allow the player to pick up the other after beating the elite four. I also want the fighting gym leader to disappear after the elite four is beaten.

3. I want to create new gym leaders in sevii island who would give out specific items instead of gym badges.

Can i receive some help on these questions? Thanks, guys.

I think it has something to do with flag 0x82C
Create a script :

checkflag 0x82C
if 0x1 goto @Rematch
goto @FirstMatch