When using
Locktime, the transaction is not valid before it reaches a certain block (or date). No miner can change that.
When I read it, I am fearful if I use nLockTime but searching clears my fear.
Can a scheduled transaction with nLockTime be cancelled. It can be cancelled so no risk to use nLockTime for inheritance but if anything change like emergency, I can cancel it to use.
A transaction with nLockTime set cannot be spent (or even put on the block chain) until either the blockheight or time is reached. In the meantime, the transaction can be cancelled by respending any of the UTXOs that make up the transaction.