I know the Nyss don't have a theme yet so most people probably haven't payed them too much attention, but the whole Nyss boat seems interesting to me. I know the Ryssovass get a bad press when compared to Sentinels but they're also quite a bit cheaper and Tough/no KD, while unreliable, can be game changing. Plus the nyss hunters were already pretty good so giving them +1 to attack rolls with the priest can't hurt.
I've come up with this Kaelyssa list which I'll try in my next couple games. Seems to me like Kaelyssa could run the nyss boat pretty well, but I'm open to hearing your opinion on the matter and play exeriences with other casters too.
I like your list, but I would consider running one group of defenders and one mechanik. This would free up points to add on Discordia. Her imprint will help alot in delivering your defenders to their desired melee ranges, plus that sp10 is sexy.