Since there's a hub world, I'm assuming you can go back and re-visit areas you've already been (I can't remember, but it might even be a requirement). Will the Drudge and Trust agents re-spawn or will we get a different set of enemies to battle against?
Not if you become their friend, then they won't attack you. --- We're glad we won you over to the fight for the earth. Currently playing: Cave Story, Majora's Mask (VC), Brawl (still), Mega Man 9, Okami, Chrono Trigger