the birth of the twins
It depends on the myth. Artemis' myths were largely relating to her worship and religion.
artemis did not because she was a myth.
No, Artemis did not have a shield in Greek myth.
Yes, it is a myth where Artemis killed the girl children (and Apollo the boys) of Niobe.
Artemis had no spouses in the original myth, although I heard a myth that said she was the spouse of Apollo.
It depends on which myth of Artemis you are referring to.
No. Artemis does not appear in the myth about Medusa.
Artemis was never 'defeated' in myth.
Artemis roamed among the wilderness and mountains in myth.
Yes, many.
She is a myth. You can not 'defeat' her.
The month of Artemis's birth is not told in Greek myth.