Below is a good link to start your research with.
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.
No, there is no myth where Artemis and Apollo are married. They were twins. Artemis never married and became one of the three virgin goddesses.
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.