I think
Mary is such a sweet, simple name. I prefer it as a first name, but I think as a mn it makes a much nicer alternative to
Marie. At one time I did have
Mary on my list of names I'd consider, but not anymore. I do still like it. If I did use it, I think I'd call her just
Mary or a fn + mn combo. I really like
Mary in combos where you use both names.
Of those three nicknames,
Molly is probably my favorite, but
Marion is very pretty.
I like these combos from your list:
Mary IsobelMary EleanorMary GeorgetteMary GeorgineMary AlexandraIn considering real use, I like the idea of pairing something a little more fresh and upbeat with it, like the examples of
Mary Isobel and
Mary Alexandra.
And my own favorites, meant to be said together:
Mary OlwenMary ColumbineMary ElizaMary FinolaMary SiobhanMary Winifred