The peace and the provocation songs definitely work with pets.
With provo, their base stats go up, their HP go up and they keep being healed some hp every 4 seconds, depending on the bard skills. Their damage output will also go up.
With peace, the amount of damage they take will go down and their regens will go up. They tank better.
I have both a peace tamer and a provo tamer with 3x120 bard skills and both do some serious damage when I use them together to hunt.