Wauw what a great strategy and learning your kids to stack.
Using a opensource wallet like minibits is very nice, maybe you can also try nostr:nprofile1qqsqcdcltmv4qanpx3p7svcufdsg9rkk00x7l2sknra4e6whkv59l7cppemhxue69uhkummn9ekx7mp0qythwumn8ghj7un9d3shjtnswf5k6ctv9ehx2ap0qywhwumn8ghj7mn0wd68ytnzd96xxmmfdejhytnnda3kjctv9uke3478 for the swaps to onchain and bluewallet (phone)or sparrow (pc)for the onchain wallet. It is always good to try different options to learn.
And a important thing to learn for them is utxo management, to consolidate their utxo's for the future. Especially now when fees are low.
Thanks for sharing your story.