Two marriages with same person - can change venue?

My ex husband and I were official (court-registered) married in a different state for a year. Then we moved to NC and registered again for a marriage license and got remarried in a religious ceremony. Both marriage certificates are legal?
The divorce took place in NC, union county where we both resided in our marital home.
(1) Are both marriages valid or is one of them null and void. If so, which one is null and void.
(2) Can a change of venue be requested after the divorce has been completed to make modifications.
a. Can the first or original marriage certificate overrule and give cause for a motion for change of venue.
b. Can the divorce findings or the divorce itself be appealed or annuled due to the dual marruage nature of the circumstances.
c. May I go to the other (first) state of marriage and make a divorce claim and other issues to be changed. Can I have the divorce be thrown out fo NC courts.
(3) The union county courts were very biased agianst me in many issues over many years. May I show this as cause for a motion to change venue to the county I now reside in (thrown out of my marital home), or ask for a federal venue (with due cause).
(4) Can the Uniform Justice Act fir Children (federal) aid me in providing good cause for a motion to change venues?
I ask all of this in the best interest of my children.

Since both marriages were between the same parties, it would seem that the second one would be void, as similar to a bigamous marriage, as the parties were already legally married.

If your divorce has been granted, you would have to file a motion set aside the judgment to reopen the file before a change of venue motion would be considered. It is doubtful that a change in venue motion would be appropriate for a divorce in NC as jurisdiction for divorce is based on the location of either party.

The majority of your questions are too complex for this forum. You sound like you need a consultation with an attorney in your area to discuss your child custody issues and how that is tied to the divorce proceedings and your desire to change venue so that you can determine the best course of action.