Does Vyvanse Cause Agitation In A Child?

My 15 years old son is on Wellbutrin xl 300 mg and adderall XR 20 mg. But last doctor appt, he was prescribed with vyvanse 40 mg to replace adderall since adderall seemed not helping. Do you think vyvanse will make him agitated? Can he take both meds at the same time in the morning? Can he mix vyvanse with milk?