I have an Aunt
Freda and had a Great-Aunt
Freda, so I'm biased. But growing up I loved the name because it sounded like "freedom." (The fact that Auntie
Freda was a 60's radical, who worked in the peace corps in Nigeria helped the image along. But I digress.) I've sometimes played around with the idea of Freedom as a fn, with
Freda as a nn. Could this work for you?
As far as the spelling, I think
Frida /
Frieda /
Freda are all fine standing alone. I've also had trouble fiding a more conventional formal name and just gave up. The obvious femininzed form of
Frederick didn't help because I couldn't find a spelling I liked to get the three syllables, "freh-DREE-kuh," that I wanted.
Fredrika doesn't do it for me.
Frederica looks lovely, but it makes me want to say four syllables, "fred-er-EE-cuh."
I've flirted with
Elfriede /
Elfreda. I still love that one. Maybe that would work instead of the ones you listed. They are all sweet and quirky.
In the end I just gave up and settled on
Freda Margaret, as is. :-)