Maybe you could use VOIP numbers for 2FA? Many VOIP providers (i.e. voip.ms) can forward SMS to e-mail, SIP client, callback URL or an other phone number. There's a cost, but I guess it's minimal, all considerations done.
Your second scenario is like a dead man's switch. It's interesting, as it could prompt you with a daily challenge that only you can answer. But I don't see how it could be implemented in a normal person's life?
Your second scenario is like a dead man's switch. It's interesting, as it could prompt you with a daily challenge that only you can answer. But I don't see how it could be implemented in a normal person's life?