I don't like the look of it: the O puts me right off for some reason.
Olive Oyl, perhaps? And I don't like
Helena either - too many pronunciation issues. But I do love
Helen and would gladly use it. From your suggestions, I really like:
Helen Rosamond or
Rosamond HelenHelen Beatrice or
Beatrice HelenHelen SibyllaCecily HelenHelen FelicityMariel Helen