I only have a surface-level understanding of smart contracts, but you'd need an oracle for the off-chain validation part of the three situations you mentioned,

I only have a surface-level understanding of smart contracts, but you'd need an oracle for the off-chain validation part of the three situations you mentioned, and https://ethereum.org/en/developers/docs/oracles/ https://ethereum.org/en/developers/docs/oracles/ seems to have some contract examples.