Alex said if you open a girl and she ignores the first few texts, then even if she responds to the 3rd or 4th text. there is a 90% chance she'll ghost/flake later

Maybe "Look at us already talking about our kids.. we're gonna be the best grandparents". You number closed her very well but there wasn't enough investment yet and if you said any of the 3 Jadons lines she'd likely ghost as 2nd is boring and 1/3 she wouldn't know what to reply

Not a good response. When going for the number there is a couple of rules and exceptions.

Preferably you want to be moving towards the idea of a date, and once you soft close you go for the number. She now is more willing to give you her number because there a clear reason, i.e. the date. There are exceptions to this such as when a girl tells you that she isn't on the app often and to add her snap, then you can you ask for the number. Or another is when she has ghosted you and then suddenly appears you can say "shoot me your number before you disappear on me again", but this is normally a hail mary for flakey girls.

In this case, she never responded, then responded. You guys actually started building rapport, however, you ended it short and asked for the number. Next time wait it out and let the rapport build, give her a better reason to give you her number.

What could have been said:
"He was always my favorite"
"It was. So what fun things are you up to today?"
"I could never have a child named bryan"