adopted & estranged

I have possibly the most complicated case and hope someone can help shed some light on a solution. My Mother remarried an Irish Citizen after the passing of my biological father. After they were married, they (both names appear on the adoption order) adopted me in 1978. My Mother got her citizenship and passport before the adoption. Years later, due to abuse, my mother divorced him. I believe I am entitled to Irish Citizenship through the adoption, however I can not get any of the documents they require from him. Do I - Option 1 - Still apply under the "I was not born on the island of Ireland - I was adopted by an Irish citizen" with my adoption papers and attach an affidavit that he is estranged so I am not able to get his documents (I have his info like DOB, name, his fathers name etc) OR Option 2 - Should I rather attempt to apply via my mother, as even though she received her citizenship after I was born, she still legally adopted me after she got her post nuptial certificate.