You have to edit the rotation.
If you look here:
That is the default rotation. You can copy this and make a version that you can edit. In the included rotation list, change the AmrPetRotationMainPet to one of the other pet rotations - you will see a list with all the different types in the tree on the left.
To simulate a tenacity pet, you use the pre-fight rotation:
It will automatically change the pet to tenacity if you have the apex predator's claw and don't have aspect of the beast. You can take the conditions off that action to always simulate as tenacity. We don't have anything for cunning in the simulator.