Is that it seems too risky and not really advantageous to play several people in the WT, namely an AS, a novice and a servant, for example. I think if Mesaana really mastered to play an AS - and the recent clues strongly point to this - this would be sufficient, considering that AS have the most freedom anyway. No need to play a novice or servant besides that.

And even if for all that Mesaana has indeed several aliases, Norine still seems to be the most likely candidate, even more than Danelle, IMO.