Hello from Korea all. My first wall:
Going with the context of the books thus far, I would have to say that assassination might be a(n almost) purely feminine pursuit. These are the Alethi we're talking about, a society where it is seemingly acceptable to abandon* the bulk of one's competition to complete destruction as long as it does not risk the kingdom*. Assassination is quite work. The Alethi High Princes (and I'll go out on a limb here and say most of the male nobles in Roshar) (Taravangian nonewithstanding) are anything but quite.
* pulled from the text of tWoK
Now, granted, those two quotes above really only say that Dalinar had nothing to do with Elhokar's bumbled assassination attempt on himself (sans weakened gemstones, of course), but they do shine on light on the way the nobles of Alethi think. Why assassinate someone when you can just call them out in a duel...or simply kill them outright? That's bold. That shows strength. That's winning. Seems to me an assassin, or rather the person who hires one, would be considered a coward. (I'll admit that coward is perhaps not the right word in this situation.)
Now, to bring this ramble a little more on point: I'm not really surprised at all that Jasnah employs assassins, either in the utilization of their typical skills or as spys/overwatch. It's my opinion that Jasnah could be considered the current Matron of her family. She's the cool one. The analytical one. The one who seeks to protect those around her. She sees what is coming and is doing everything possible to find a solution. (Navani is a woman of gossip and passions, a politican and dabbler of fabrials. I'm not saying this doesn't make a matron, but it does seem to me that Jasnah is the one doing what it takes to keep her family safe. Afterall, Navani returns to the Shattered Planes because she feels she has not place in the capital. ... .. ...I do like Navani as a character. I really do. Ahhh. Never mind.)
I'm not sure, but I don't think fighting and assassination really have any relation to one another. In the context of the subject matter, fighting involves banging one's sword/spear against their enemy's sword/spear until one is no longer able to do so. Assassination, on the other hand, is killing someone. There's no real fighting envolved...or at least I'm sure the assassin hopes so. All that to say perhaps assassination is gender neutral.
One final note: If we're to look for Lyss on the Shattered Planes...shouldn't we be looking for a male character?