Î might have not made very clear what I meant by this. Mirian originally had imagined the Council having nine members. But in the process of finding those members, she met Galor and Azira, whom she thought should be given a place in the Council that was not one of the already existing ones. So, she made two more places for them. On 2972 AF, she had found the 8 members she was looking for plus Galor and Azira, that making a total of 10 members (excluding Mirian).
They were against stereotypes. Tetraprosopus wasn't! :P By the way, do you know what Tetraprosopous actually means?