Who were the first sisters to swear oath to Egwene?

The bulk of it was made up of the Salidar Six, minus Sheriam Bayanar who was already Egwene's Keeper of the Chronicles. The sixth member of the council was Nisao Dachen, who had also sworn an oath of allegiance to Egwene. She used the oaths they had sworn to her to force them to get themselves chosen as the representative of their respective Ajahs. This was no easy task for some of them, but they managed to do it. This meant that she was surrounded with advisors that she felt she could trust as much as you can trust any Aes Sedai, at least.