You'd take Fog Breath over War Cry?
I usually let the buff/debuff to my party, so I actually take none of them, but have both on my party.
As you apparently have a physical build, your MC will be your main damage source, so his main role will be to use Focus+physical skill. To not let his MP go to waste, you have to take a couple of either healing and/or buffs on your MC (as support for your main healer/buffer), as a side role. I chose healing, as your MC is the only member sure to stay alive to heal (as else its Game Over).
But to answer your question: evading a hit is better than to take less damage, as it'll consume one press turn of the ennemy. Likewise, not missing is better than doing a bit more damage.
But War Cry's effect is more reliable than Fog Breath's, so it's up to you.