It's this possible?

Hello everyone!

I just made a list of changes that my hack will include, and I would like to know if they are possible to do and how much hacking they would need.

Here it's the list:

• Create a item to revive Leo and add him as a 15 playable character.
  You will likely need ASM for this and free space for the code
• Add a secret room at the Colosseum with a secret boss.
  Same as aboveMake the economizer only reduce mp consumption by 75%.This would require editing the formula so ASM as well.Put the Dragons that were on Kefka's Tower in other locations.Editing the bosses is easy but for the dragons you will need to edit the events.Add new bosses in the places where the Dragons used to be.Same with the dragonsMake the man in Narshe only give you the Ragnarok magicite and give you a hint about where it's the sword.The wiki has a list of events so you can edit this to only give you the magicite however, this might require more event editing other than just a few bytes.Buff the final boss.This is easy. FF3ME can help you with this.
• Add some new weapons like Ice claws.
  If you want to edit currently existing weapons then this is also easy. FF3ME can you to do this.

I wonder if this would fit on a expanded rom and if the expanded rom would cause bugs or glitches.