1) Yes, they could have initiated the investigation themselves, it could have been an anonymous complaint
or they could have a named complainant, but they do not have to disclose any of that to you unless the complaint is substantiated.
2) This would be if they substantiate the complaint.
3) They can ask for proof of her payments on the mortgage and proof she is not residing there with you.
4) You do not have to let her in.
5) You can alert the school, but they cannot stop them from getting information or questioning your children without you being present. They do not need your consent to speak to your children in the investigation.
6) They have a right to obtain information from his apartment complex and job and can do so with administrative subpoenas or even with criminal court
7) Not necessarily. The DA has the sole discretion as to whether or not to pursue criminal charges and just because you repay does not stop the DA from pursuing criminal charges unless you have negotiated some written agreement that they will waive criminal charges for repayment.
8) Yes, you would have it on your record and you would be denied future benefits.
9) They do not have to release any information to you prior to concluding the investigation at which time they will send you a letter with their findings.
10) Depending on the outcome of this investigation they can notify medicaid, but it does not mean medicaid is currently investigating.
11) No, these would be independent.