The marital status of your biological parents doesn’t matter. In most states, the father is presumed to be the legal husband of the mother, but if your mother’s husband never claimed you and his name isn’t on your birth certificate, and none of you WANT him to be claimed as your legal father, it’s likely well past the time for any automatic assumptions to kick in.
Just answer the questions as asked. Mother? no change. Bio father? named. Current status? never married.
This shouldn’t change anything on the FAFSA unless your bio father has been contributing more support for you than your mother. On CSS, again just answer the questions.