Note that I am not licensed to practice in your state. This is not intended as legal advice. Please check with an attorney in your state.
This is very complicated to fully answering in a forum such as this. Basically what you need to do is find a local family law attorney that does adoptions. Your new husband needs to adopt those children.
Hello - I am a MD attorney so can answer your question in accordance with MD law. There are several issues you have raised: 1) Can you change your daughter's last name to your husband's? 2) Can you have your husband obtain guardianship of your daughter without obtaining permission from her birth father? 3) Can your husband adopt your daughter without finding her birth father? Here are my general answers without knowing more specifics about your situation. 1) Most likely you can change your daughter's surname without finding and obtaining permission from her birth father, as long as the name change is for no fraudulent or illegal reason, like hiding your daughter from her birth father. 2 and 3) Actually, legal guardianship and adoption are similar. You will need to look for the birth father in order to have a Court grant either guardianship or adoption to your husband. That being said, the process of stepparent adoption is not difficult in MD, and you may only have to send notice to the birth father at his last known address. You may have to publish a notice in a newspaper of general circulation where he lived the last time you knew his address. It is very likely that he would not come in to contest the adoption. However, it sounds like there are some facts here that may give you pause in trying to find him. If you don't pursue a stepparent adoption of your daughter, there are some legal documents that you should have prepared to protect her relationship with your husband, for example, a Will and a Designation of Standby Guardian.