Did nuns participate in the councils? Are there any records of this? Though I'm more curious about the first council, I'm generally curious about their participation in any of them.
The Ariyas are "breast born" sons and daughters of the Buddha and they sometimes address each other as elder brother or sister as a mark of respect, according to their accomplishments. 

Given that it is a council of Arahants, would it even occur to them to notice  that there is a distinction, even in terms of class or sex amongst them, and that distinction is marked enough to make a separate representative body, which participation somehow adds or detracts something on the authority of the council?

The council of Arahants would look more suspicious if it was thought that some of those distinctions were relevant and recorded.

The patimokkha is different, in that, later it was made up of ariyas and putthujannas and the rules of the women were slightly different and more than the men.