Future directions that I would take to elevate user experience with this app would include auditory feedback for younger children who still struggle to read (e.g. if a child selects the body scan activity, they could get feedback verbally confirming the activity they chose).
I would also incorporate activities that require physical interaction, such as, if the child feels angry, the activity could be to hold the phone or tablet in their hand, and shake it, to release their anger, while the screen slowly turns from red to blue indicating a change in state and encouraging calmness.