It doesn't have to be a kill list, that's what you're not understanding. Medicalizing dissent, creating registries of potential scapegoats and vulnerable people to target or practice on, that's the purpose. They create an outsider group to stigmatize and then broaden the definition as necessary.
You need to look at this step within the totality of the conduct of the regime so far. They are already rolling back child labour laws and openly talking about the need for a baby boom. Children are one of the most vulnerable groups in society, especially in conjunction with other factors like a migrant background or being in foster care. How many kids are in precarious situations with either absent or completely disempowered parents?
They're already putting unattended children in front of immigration judges without legal representation, if the state simply kidnaps and disappears the children of people it's trying to deport without due process, what's to stop them? What do you think these ghouls might want to do with lists of kids?
What you need to recognize is that this is the sort of registry that would be directly accessible by those surveillance initiatives you mentioned. It's not duplicated effort, it's part of the same effort, this is just one of the ways they are trying to define their enemies and undesirables.
If you think that eugenicist views being more common at the time is any kind of defense you're sorely mistaken, and if you think there's much of a difference between someone who kills kids and one who tries to decide which kids are worth killing first, you're wrong.
That first reply was for everyone else and reality check for you, but seeing as you seem intent on ignoring it I'm not going to bother wasting any more of my time interacting with you. I truly hope you come to realize how fucking disgusting your perspective is, I've tried to explain it to you but I can't understand it for you.