Athena's parents were Zeus and Metis and she didn't have any siblings!
Gaea, his grandmother and Metis, his first wife.
Athena relatives were Zeus (her dad), Metis (her mom), she had no siblings, no children, and no spouse.
to do matchmaking
Swallowed them; Zeus with the aid of Metis later made Cronus disgorge them whole.
hecate
No. Metis, her mother, was not married to Zeus. Athena can't really have step siblings if her mother was never married.
Neither. She was Egyptian.
Nausicaa
Poseidon did not come out of the stomach of Kronos, he and his siblings were spat up when Metis and Zeus tricked Kronos into disgorging them.
Persephone is the Greek goddess of innocence and queen of the underworld.
Yes; Hera is daughter of Kronos and Rhea.