You could safely sleep with a 1 year old toddler but I would not recommend it as you could potentially roll over onto the 1 year old and then cause injury or death.
An adult body accidentally rolling over onto the 1 year old could be deadly pretty quick because the weight of the adult body versus the weight of the 1 year old.
It would be too easy to roll over onto your 1 year old who then might not be able to roll out of the way if you roll onto them.
Sleeping with a 2 year old would be more safe as the 2 year old would not get crushed as easily as a 1 year old.
I would recommend keeping the 1 year old in a crib or baby bed until they turn at least 2 years old and then if the 2 year old wants to sleep with you in the same bed for awhile then you can do so.
It's not worth risking the chance of rolling over onto the baby and possibly injuring them or killing them.