Honestly, for kids I’d just use a custodial wallet such as WoS or Blink. If I were to stick to non-custodial, I’d run a node on Voltage and use LNbits to create accounts for each kid. Then they could use Blue Wallet as the inference to those accounts. A middle ground solution would be to use Aqua which works kinda like Muun, but stores your balance on Liquid so it’s much cheaper.