Ma Dincht has Zell's card because he was adopted by her not just because they met one time.
Of course.But she isn´t his mom.
As I said,Laguna might have meet Squall´s father on Winhill.
I think JUlia was a queen on Ulti´s castle.
I say that because we see a picture of a queen with black hair and red clothes on the castle.
That alone was a better evidence to my theory than the ones to support Squall=L+R.
I used the binary association method on this case.