Thanks to the forums over on legendoflegaia.net, here's some mechanics info:
http://www.legendoflegaia.net/forums/viewtopic.php?f=66&t=800I haven't finished parsing all of it myself and someone who's better at finding the important points may want to distill stuff for the topic, but the BIG IMPORTANT THING is that Noa's Love moves don't actually have 100% charm! They actually do 13 separate 50/50 attempts at inflicting the charm throughout the move's animation. Thus, at a composite, it's actually a 99.988% chance to charm :V
They cracked the damage formula too, it's complicated as fuck and while I'm not going to go into the exact formula here, the important parts are that damage increases by 1/64 every hit of a combo, and every 256 points of current HP the attacker has increases damage by 1!!! >_>
Other things: elemental properties!
Wind attacks do +1/16 damage against Earth-aligned enemies, and vice versa.
Fire attacks do +1/16 damage against Water-aligned enemies, and vice versa.
Light attacks do +1/32 damage against Dark-aligned enemies, and vice versa.
Lightning attacks do +1/32 damage against all of Fire/Wind/Earth/Water aligned enemies, but -1/32 against Dark-aligned enemies.
Every element does -1/16 damage against enemies of the same element.
Finally, since it might be useful for a Futurama, here's the damage ratios for PCs using Seru spells.
Vahn
Earth - 95%, Water - 40%, Fire - 100%, Wind - 70%, Lightning - 70%, Light - 85%, Dark - 85%, Non - 80%
Noa
Earth - 40%, Water - 95%, Fire - 70%, Wind - 100%, Lightning - 70%, Light - 85%, Dark - 85%, Non - 80%
Gala
Earth - 85%, Water - 85%, Fire - 85%, Wind - 85%, Lightning - 100%, Light - 95%, Dark - 60%, Non - 80%
These get plugged into the damage formula for the spell, which is:
offense = seruHP + rnd(0..seruINT+1) + casterINT*2
defense = rnd(0..enemyINT / 2 + 1) + (enemyLDF/16) + (enemyHP/256) + (enemyUDF/16) + (enemyINT*2)
damage = offense - defense
Yes, the HP and INT of the enemy from whom you absorbed the spell are a factor in the damage. Every time you level a damage spell up, the damage increases by 12.5%.
One last random tidbit: the US version of the game is harder. Based on what they could find looking in the code, it appears that the localization boosted most enemies' ATK by 25%, INT by 12.5%, and UDF/LDF by 100%.