Yes; however, doing so does not establish paternity.
In the US, the parent[s] can give the child any name they choose. However, doing so does not establish paternity.
No. Only in Utah is his consent not needed, just a notification.
THE ANWSER NO WAY
She can try, but he can get an injunction.
yes
If there is a custody agreement in place through the courts, the mother cannot take the child out of state without the fathers consent. If there is no agreement in place, the mother does not have to have the fathers consent.
A mother cannot move a child across the country without a father's consent. However, if it is spelled out in separation or divorce papers, she can.
You indicate they have "Contact", but what is the status of Custody? If the Father has visitation, partial or shared custody, legal& or physical....No, you cannot change the Surname of the child without the Fathers explicit consent!!
IF THE MOTHER HAS SOLE CUSTODY
Yes, but only if the birth father's parental rights have been terminated by the courts.
If there are court orders regarding visitation and child support and custody, you will need his and the courts consent. The court orders have to be followed.See related question link.
You cannot take a child out of the country without the consent of the other parent.