Hello FBW
My comments about children in business class were meant to illustrate, as you mentioned, that it's actually the parent rather than the actual child who dictate their behaviour.
I've sat next to screaming babies on numerous occasions and it doesn't bother me at all, probably because I've listened to my own kids screaming when they were babies. You have all this to look forward to
In my experience most people are extremely understanding whether on a plane or elsewhere.
Enjoy them while they are young as they grow up
very quickly