My daughter is about to turn four in October. Her biological father has not had any contact with us since she was 11 days old. He is not on the birth certificate and did not sign/fill out the paternity affidavit. I have paperwork showing my the refusal to fill the paternity affidavit out (on my part). My husband and I are looking to have her adopted and given his (my married) last name. He has been the only "father" she's had since just after her first birthday. This coming May we will have been married for 2 years, and I was not married to her biological father. My questions are: 1)what rights, if any, does the biological father have to her? 2)Do I need his consent in this adoption? 3)What requirements are needed in the adoption? 4) What will be the costs? 5) Do I have to have a lawyer?

I live in Indiana if that clarifies things. I know laws are difference elsewhere. All helps and suggestions are greatly appriciated. Thank you!

Yes you need to hire a lawyer to get through this and to tie up any loose ends. You will have to contact the bio father and ask his consent. If he gives his consent then its not a huge cost involved and you can get a name change done at time of adoption. If the bio father doesn't consent then its going to cost a lot more.

The only issue that I have is that I have had absolutely no contact with him and have no idea how to contact him. Not even sure if he's still living in Indiana. Didn't keep any contact info for him and wouldn't know where to start looking.

And this will add to the cost, since the court will have some specific rules on what you are expected to do to find him.
Do you know where mother / father or brothers / sisters are at and can find him though that. Is his name unique enough that a simple search may find him.

If he can't be found, notification though publication ( a lot more cost) will have to be done.

So a few thousand dollar court case ( with fathers consent) can turn into several times that cost if father can not be found.

Was there never any court ordered child support ( which normally helps makes them want to sign over their rights)

But the bio father needs to sign over his rights or a big attempt to find him made.

The biological father of a child ALWAYS has the same parental rights to the child as the mother. Whether the father is identified on the birth certificate or not. The difference is that the father has to actively enforce those rights. That is why a court will require that the father agree to a step-father adoption (or any adoption). However, laws do understand that the father may not be reachable. But they require a good faith effort to make contact.

So your first step is to hire an attorney who can properly prepare the paperwork and go through the proper steps to satisfy the courts.

The biological father and I have never been to court over anything (support, visitation, etc.) As I have said I haven't had contact with him in almost 4 years. As for reaching him through family, that is also a little hard. I have found out almost everything he has told me about them was a lie. There is an aunt living in Michigan I think however I can not remember the name. I do know it isn't the same last name though. He told me his mother had died in a crash and his father and step mother were living in Florida. He also said that his step mother was dyaing due to not taking care of her diabetes. Thus the reason he left me. However this was almost 8 months before my daughter was born. In that 8 months we were in contact, but

This is the time when I found out he had left me for someone else who was also pregnant and due weeks after me. He wasn't there for any appointments, the birth, nothing. He showed up 2 days later with small gifts and was seen once more about a week later. I know this all makes me sound like a horrible person, not knowing anything about him but getting pregnant with this guys baby, but we were together for almost a year. As I look back I realize the whole thing was a lie. And because of this I am determined to make sure my daughter is ALWAYS given the best of everything. She has always bee surrounded with friends and family that love her. My husband loves her unconditionally and says that we are willing to do any and every thing to make sure HIS daughter is exactly that... his. Thank you for the help and I would still like more if someone has it. I will be sure to post our findings.

None of that really matters. You still have to make a good faith effort to contact him according to the rules in your area.