Before you go to 'Hocus', buy lots of magic items from the item store and make sure that all your characters are atleast at level 6.

Sandra special soldier:
Only use physical attacks against him and don't waste your magic items to try to defeat this guy. When he transforms into three, the one that uses magic is the real one. [If you can't figure out the real one, than keep doing guard]

Kongol:
This guy is very strong!!! Only use magic against him. [If you use physical attacks than you will be counterattacked with more damaged hp to you!] Keep using magic attacks and using the option 'Guard' which will restore your HP.

More damage
When you are in battle with a character that can do Additions and you select Attack and you are charging at the enemy as the outer square closes in on the inner square press the X button just as the two squares hit and if your timing is done right you can hit them an extra time giving you more SP and dealing out more damage. With different Additions you can do more and more damage.