No. The card only works at the tuck shop of your child’s own school. Not at shops outside the gate, and not at another school.
Tell the school. The card holds no money, so whoever finds it cannot spend your balance. The balance moves to a new card, which costs UGX 20,000.
The card itself carries no money, only an identifier. Top-ups are handled by Yo! Uganda, a licensed Ugandan payments provider, and every purchase is recorded so you can check it.
No. Nuvora opens in your phone’s browser. You can add it to your home screen from the browser menu.