It's kind of hard to say about Cyndane's relation to Nynaeve. As I look back on it, it's kind of an AS sort of response. I asked how Cyndane compared to Nynaeve in strength - that's when he stated that Cyndane was very weakened in the strength - he went on this so hard that it sound like he was saying she was very weak (this is where the confusion comes in because I think he was trying to avoid confirming her directly as Lanfear reborn). The implication is that Cyndane is weaker than Nynaeve. However, it wasn't stated as such, so there is room for interpretation.

He wasn't all that dismissive of Mesaana - just certain that she was weaker than Nynaeve. With the emphasis on how close Nynaeve and Semirhage are in strength, I would intrpret Mesaana to be weaker than Semi.