Hi, I'm not sure really
We got the first female from the Shop and she dropped 2 nights after we got her..
Same story with the orange mollies, the night we brought her home from the shop she had babies
No idea how many there were, I fished about 14 black and white ones, and a week later about 12 orange ones. I still spot them swimming around in the main tank but the creche is full ..... for now!
I didn't even realise the fish were pregnant, they didn't look particularly big
So sorry I don't know the answers to your questions
But yeah they are cute!