US Immigration from Ukraine

My fianc has two children (11 & 8) with different fathers. She says they are not on the birth certificates and rarely ever see the girls. The girls have her surname. She says on the birth certificates she listed fake names for the fathers. I am under the impression that the fathers will have to give permission for the girls to come to the United States but she says that is not so. I am also concerned about the fake names on the birth certificates. It has been five months since our K-1 a visa application was received by USCIS so I expect a response soon and I want to be prepared for what is next. Thanks for responding.

If my parents received a 221(g) during the IR5 interview, to find a joint sponsor, how much time do we have to do so? Like how late can we respond to the request?

Do I have to provide the original of my divorce decree for my parents' interview?

I am the petitioner. Single, but the last tax returns were filled as "married, filling jointly or separately," we divorced earlier this year.

Do my parents have to have original or can they get away with the copy?

So I applied for both of my parents for IR5. My dad is ahead and his interview is upcoming. The NVC send me a message I don's qualify for the sponsorship. I don't make much but I though we could use the assets of my dad in his home country. Do we fill out the I -864 A as well?

If we were to be asked to get a joint sponsor, how long do we have after the interview to submit the document?

Does anyone have a list of questions that they would normally ask the parents during the immigration interview? For IR5.