I think Eyeshigh knew because of her frequent sendings to Skywise. He may have answered her. I dont think Toorah could send at the time she was carrying Leetha, but Savah picked up on Leetha's name long before she was born. Rayek learned Leetha's name from her. Savah seem to know everything worth knowing. Kahvi couldn't know Teir being a boy when she concieved him. She does send,so she may have sensed it at some point before he was born, but she couldn't do anything about it one way or another.