I would structure your circuit, alternating upper body and lower body exercises. Which will help to keep the heart rate up. Of course keeping the lower body exercises appropriate for planter. Maybe mat work, side lying leg raises, clam shell, mule kicks, fire hydrants, all come to mind first. Cardio wise, why not think a little unconventional, have her hold v-sits and toss a med, v-sit and cross punch, the move I call, the dead bug (lying on your back, or v-sit position, arms and legs straight and “scissor ” arms and legs). There are several other multi-jointed or combo movements you could up with that would help with the heart rate.
Hope you find this helpful!