IMO
Mia is not good as a MN - it has to be FN. And I think combos like
Mia Evelyn or
Mia Rose will go well. Just don't choose those trendy and/or kree8if names as MN; it would ruin a lovely name like
Mia. ^_^
Of your list I like
Emma and
Megan, more than I do
Mia.
Emma really sounds elegant to me and will age better than
Keira or
Carys. And all the Megans I know are beautiful and/or graceful.
Mom to Olivia and Aunt to Joseph, Michelle, Erica and Alex