paternal acknowledgment

good morning.i have 2 kids who are using their dad's name though me and him have no record of marriage in NSO and i got a singleness certificate too.in their BC it shows that a marriage happened between the 2 of us.my questions are:
1) are my kids legitimate or not
2) if i want to get passports for them, will there be a conflict with regards to their names since i dnt have Marriage Cert to show.Is DFA going to follow the names in their BC?
3) is it possible for my kid's dad to get an affidavit of acknowledgment of them and to register it late?
4) what is the best and fast thing i could do because i want to get my kids asap

my deep appreciation and thanks for advices you could give me.Regards.

Geez! I doubt that you will be granted a passport for your children by the DFA. They do require marriage certificate if you wish to get your children a passport. Using their father's name when you are not married can conflict situation for your children. Although he acknowledge the children and they are using his surname, you made a mistake putting on their birth certificate that you are married. It would be easier to prove that the kids are using their father's surname because they were acknowledge by the father although you are not married, therefore the DFA will not require marriage certificate from you but they will require a letter from the kids father allowing you to take the kids out of the country.

imo, the proper remedy will be to hire a lawyer and file a petition to correct the birth certificates first.

what if the case is parents are actually married but not registered to NSO since it is solemnized abroad? Will DFA acknowledge the marriage certificate?

Of course they will! have it authenticated where you got married at the Embassy abroad, before applying for your child passport.