Responses
It might, or might not be, but probably, the third child is their child in the past, and was also reincarnated. I'm not that fluent in Korean but I know how to read Hangeul.
Spoiler: I thought the 'dragon' called him "mother". That gives me the speculation that their son from the past is also the latest child.
in raw there's still have side stories, the child grown up... and they have 1 child again it's a boy (alpha)..