I love the sweetness of
Mary. It has a very pleasant sound. It's just too bad that it's been overdone to the point of saturation so that in many minds, it's considered to be dull, dull, dull.
Molly is my favorite of the three nns you list.
I would use
Mary but I tend to prefer a double name.
My faves:
Mary Katherine (
Mary Kate)
Mary Elizabeth (
Mary Bess,
Mary Beth)
Mary Isobel (
Mary Bel,
Maribel)
Mary Eleanor (
Mary Elle)
Mary Alexandra (
Mary Alex)
Mary Claire
I even sort of like
Mary Faith and
Mary Grace although they are a tad too religious for my tastes.
Of your combos, I like:
Mary Cordelia -- I love this!
Mary VictoriaMary Isobel -- I see we have similar tastes here.
Mary Eleanor -- Ditto.
Mary Alexandra -- And also here.