So why weren´t their parents mentioned?Didn´t they respect their parents?

If the husbands got there before Ragnarok then they must have left their wives before they were crystallised, which seems entirely unlikely given that Vanille was only 19 at the time.
Some cultures enable young marriage.Women can get pregnant at 19.Do note that they were ancestors,not grandmothers.

It would be insanely unlikely that they would be able to reach Cocoon at all - far less likely than, say, meeting someone who has the same name as a gang that you lead.
Flying Eidolons?I already explained this before.
Before Ragnarok there was no purge.So a Fal´Cie would let them enter after researching whether they are a menace or not.

This would mean that no man would willingly go to Cocoon as they were all brought up in the same knowledge that it is a bad place.
Traitors exist everywhere.Persons who change their mind also.It also explains why the woman would like to forget them.