Names like
Margot (ending in -ot for a girl) are exceptions. Normally a guy will have -ot ("o") and a girl -otte ("ot"). The name Margotte exists, but haven't been used since Middle Ages. It would sound very old dated to a French person, but not ridiculous at all.
Normally, if you see a French name ending in -ot or -otte it's very easy to guess if the person is male or female.
Jeannot is male,
Charlotte is female,
Charlot is male,
Lotte is female... It's the same with -ent and -ente, -et and -ette, -ien and -ienne... Female names tend to end with a -e or a -a.
As for Melilot, I guess it's ok since it comes from the name of a flower, and a flower is "feminine" enough, so they didn't need to feminize the name. I've never heard of a Melilotte, but who knows... Melilot is very rare too.
I also wanted to say that Melilot is not prn. Me-lay-lo. In French, a "i" can only give a sound like in "
Inge", "yell", "image"... No "ay", no "hey!", no "bed", and so on...