Final Fantasy III NES Tweaks

As for suggestions to improve the game, some points that I can think of off the top of my head:

1) If possible, fix the Item Upgrade bug and Magic Duplication bug. Both of these bugs allow you to basically cheat yourself through the game, either by giving you overpowered equipment early on or by multiplying your magic spells for infinite money.

2) Some job classes are severely underpowered and/or lack proper equipment. I'm looking mainly at the Bard and his really small selection of only three harps. Maybe at least increase the harps' attack power and/or the amount of equipment the Bard can wear.

3) The Terrain magic spells backfire a bit too often for my taste. Either decrease the chances of backfire, or decrease the damage it does to you. Several Terrain spells are also instant death spells, but with a rather low probability compared to the black magic spells Break2 and Death. Would it be possible to make Terrain magic selectable from a sub-menu instead of the spell being selected randomly?

4) With all the end game bosses being resistant to Holy, the Holy spell is pretty much useless. Remove Holy resistance from all bosses in the final dungeon.

5) Incorporate the dummy enemies Captain, Fury, GoldCoin, Phoenix, Hobgoblin, Spriggan, Hydra and Terrible Dragon at appropriate locations. Also, increase the encounter chances for Yellow Dragon, Green Dragon and Red Dragon (it takes ages finding them. On my first couple playthroughs, I wasn't even aware they existed.).

I'm thnking numbers 2, 3, and 4 shouldn't be too difficult to implement with the knowledge we already have about the game. Not so sure about numbers 1 and 5, though. Do you have any information about monster formations and where they are stored in the rom, by any chance?