Tailwind dispels the Hydrangea accuracy debuff on melee attacks,* and spells(fire/light) are better than bombs if you have the MATK for it since their attack debuff doesn't reduce MATK.
Ogre Commander is tanky, but Ogres are extra vulnerable to being attacked from behind, his attack pattern is/was very predictable(attack, attack, windup, defense debuff IIRC), and his damage isn't very threatening if he can't land his windup martial to debuff your DEF. The Goblin add is also weak to just about every type of magic, so killing it with fire is a cheap way to get tactical advantage.
The Low-Demon's clones have 1 hp each(2 on nightmare). A single AoE attack(e.g. slash) by John or Aura should bring the 5 back to 1.
*I think storm is supposed to do this too.