If we're taking the names as they're stated in the OP, I prefer Megan as a feminine name, because I actually think of Morgan as masculine. But of spelling variants, I actually think Meghan looks better than Megan despite having an "extra" letter (Megan looks like it's missing something, for some reason; I'm of the same opinion in Rachael vs. Rachel).
However, I vastly prefer Morgana to all. When I first learned of the tales of Arthur and his Knights of the Round Table, Morgana le Fay was the name given to the sorceress; and I didn't learn until years later that she was actually known as Morgan in most translations. So Morgana was the name that stuck with me.
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Please rate my personal name lists:
www.behindthename.com/pnl/69381www.behindthename.com/pnl/69381/109399www.behindthename.com/pnl/69381/91835http://greens-end.myminicity.com/