Your fiancé would be able to adopt your daughter if all the criteria are met. You have said nothing about what the father would do if served with papers terminating his rights. You need to think this through and consult with an attorney.
Before any statement alleged to have been made by any defendant can be used at trial there is a motion to suppress that statement made by the attorney. A hearing is then held where a judge makes a determination if all, part of none of the statement can be used at trial. Usually the prosecutor is looking to include any statement of the defendant in which he or she makes incriminating statements saying they did something that was part of the crime charged.
the answer is dependent on whether a plea bargain is entered into. In many locations they will allow you to plead to a local law violation so that the locality recovers the funds. Hire an attorney in the area to represent you.