Marriage might solve the "Villagers seemingly embrace at random"

But I think marriage is very confusing...

What will the married couple's children do?

Note, "Johnny" and "Turner" are last name.

Bass Johnny and Tuna Johnny have a boy called Sam Johnny.
Cook Turner and Soda Turner have a girl called Cola Turner.

Sam and Soda grow up and married, had a new surname Coral.

Sam Coral and Soda Coral have two children called Tita and Mua Coral...

Tita and Mua grow up.

Who would they marry?

It's really confusing for me.