Cross Edge

Self explanatory, but note that equipment effects don't count for this. When your characters level up, you'll be granted extra points to level any of 5 attributes - Agility, Vitality, Strength, Intelligence, and Luck. These will level on their own automatically in addition to the extra points you assign. You may save points from level to level. PP can be used to raise these stats as well. While in the menu, go to 'Status' and hit triangle to bring up the same level-up screen where you can upgrade these stats on your party members. PP appears to be rewarded for story-related and sidequest battles.

A quick way to get all 5 trophies at nearly the same time is to save up your PP; When you've got enough to make one of your characters hit 300, save first and then do it. Load your save, do it again on another if they're close enough. That way, you don't actually need to build everyone up.