Hi:
Have you found Marianne yet? The one that shows up in CA doesn't seem to match the age you have given in your post. If you haven't found her may I suggest you request "non-identifying" information on the birth parents from the state of OK? This will hopefully verify some of the information you have on Marianne...especially her age and place of origin. Here's a link about that:
http://thenationalcenterforadoption.org/wp-content/uploads/2...As the child of a deceased adoptee you also have the right in OK to request they open the adoption file through a Confidential Intermediary. The degree of information you might get always varies from state to state. You can read more about it here:
http://thenationalcenterforadoption.org/wp-content/uploads/2...I think the most important thing is verifying Marianne's age and if she was, in fact, from Ohio. There's a Mary Ann Timko on the 1940 census there that matches her age (b abt 1936/37) that could be her, but any shred of additional evidence you could gather would be helpful. Once you have additional information please let me know and I will review it and let you know how I think you might be able to proceed. I am a volunteer adoption researcher with 30+ years of genealogy research experience and would like to try to help you!
Good luck,
Terri