He he. That's ok. I also use that Nu in the Cursed Woods/Hunting Range to get my techs up, one time I had Lumunair before fighting Masamune! 
Now that's how you wreck the balance of the game.
Maybe a lock on certain tech--no, that would be unfair to the player...the lock for techs on Crono, Marle, Lucca, and Frog until you visit Spekkio is bad enough.
As for Charmed stuff, most enemies will have crap unless they area really tough or they are a boss that can be charmed. The Anubis bow (second best bow for Marle) will be charmed of Cyrus's ghots (most people will never know about this one as Cyrus's ghost normally has nothing) also, you obviously can't get this after the Northern Ruins is complete. So it'll be sooooo easy to miss. He he.
No. I am firmly against this sort of thing, because it is EXACTLY like the Zodiac Spear from Final Fantasy XII in its hidden method...leave hints for where it might be, at least...I also question the need for placing the second best bow for Marle there when there is an inferior bow in the ruins themselves and another inferior one on the Mystic Mountains.
I may be able to dynamically change the charmed/dropped item before the battle begins. If I can do that, then we could have every enemy drop a common,uncommon,rare item as well as a common,uncommon,rare charm item! That would be primo.
That would definitely be nice...a dynamic charm system and item drop system would work wonders. I would caution that we do not use this on certain bosses, thus making their charms and/or drops always the same regardless, though perhaps for minor bosses, such as, say, Yakra, it'll be fine.