Activating an iPad Pro 4G for underage Apple family account member

We purchased an iPad Pro 4G as a gift for our daughter. She is now 16, and has been a family member on our account for years. She has her own iPhone, but still needs permission for purchases.

When she started activation with her own iPhone, she got as far as "Connect to mac or pc with iTunes" 3x.

We have tried connecting her own iPhone, and my Powerbook. No connection either way.

Do I need to start from scratch activating the iPad Pro as the owner, then transfer access to my daughter? Her upgraded phone was just device to device, iirc.

Thanks.