I'll just jump in here without reading the previous 14 pages.

I've two adult sons with whom I have little contact.  I want to leave them each 1 bitcoin but probably more.  Right now I'm thinking of 3 Trezor One wallets.  I've never used a wallet outside of Bitcoin-QT and use Coinbase.  If I have my btc in those 3 wallets, 2 of which would be marked clearly with the sons' names and left with an attorney (if the attorney would agree to  hold them), what information would I need send the sons so that after I die and the Trezors are sent to them, they can open and do with the btc as they please?  I have a problem with executors as experience has shown me family can't be trusted.

Would this approach be a mistake?  I know nothing of US estate law.  I think one could give family $10k/year tax free to them, understanding I would need pay tax on those $10k btc.  Not expecting to die today, perhaps transferring $10k worth of btc per year over time to the wallets designated for them could be done?  What would they need do to acknowledge receipt to the IRS without they're having the wallets?

Thanks.