I can't for the life of me find a difference between 'active' and 'wait'. Isn't wait meant to wait for you to chose what to do without the enemies attacking you? Standing there doing nothing in both 'active' and 'wait' has the same result, and the enemies still attack.
The Active/Wait system is mostly consistant in Squaresoft games.
Active implies that time continues to elapse while you are in the Tech/Item menus. Enemies still attack, and other character time bars continue to fill up (assuming you are waiting for them to be ready for a dual/triple tech).
Passive implies that time halts while you are in the Tech/Item menus.
This game isn't FFX, where time is dependant on your character's moves in a turn based type of situation.
If you are not in the Tech/Item menu, time continues to elapse.. even while you are selecting targets with the Attack command.
Also note that regardless of whether you are in Wait/Active mode, time stops when you or an enemy makes an attack.