"Finna" is a slang / vernacular word in English, existing as a contracted form of "fixing to" (analogous to "gonna" and "going to," or "wanna" and "want to"). So I read Finna, and I ask myself, "Finna do what, exactly?" It doesn't look like a name to me, sorry.
The Frisian name Fenna, on the other hand, I find quite charming.
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