If there was a forger, don't you think they might have access to a Polk Directory too, and picked a name out. OTOH, if she routinely signed as local registrar, there should be other BCs from the period with her signature.
Did they check that Polk Directory for the woman who signed the Nordyk twins certificates as the Local Registrar? If she worked for the hospital, we have problem, if she worked for the State Department of Health, that would indicate that the local registrar was a state, rather than hospital, official.
I will say that the signature does not look like one by a woman of that era, who would have been taught penmanship, when she was in school. My mother went to the archetypical "one room schoolhouse" in a Nebraska corn field (or wheat or sorghum). She was 33 years old in August of '61. Her penmanship was much, much better than that, and she practiced the exercises she'd been taught to keep it that way. The signature on the Nordyke twins' certificate looks more like what I would expect from someone of that era, although not as good as my Mom's was then, and the copies I've seen of those certificates are pretty poor, still you can make out that her first name was probably Beatrice, her middle intial "L" and her last name as "Yqusin" or "Ygusin" or "Yqusia" or "Ygusia".
http://wtpotus.wordpress.com/2011/07/18/1961-hawaii-department-of-health-registrar-identified/
I think everything you asked for is explained on the above website.
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