Dhavaer

Elhokar is also much younger than Jasnah, who seems to be an infant at the time of the flashback.

As far as we know at the moment, the type of gem is only relevant for soulcasting.

The varying value of gemstones is based on their soulcasting utility. So emeralds are most valuable because they can be used to make food, while diamonds are less valuable because plain crystal isn't something they need much of.

I think Jasnah's problem with Navani is pretty easy to work out by looking at their relationships with other people: they have massively incompatible relationship styles. Jasnah needs a tremendous amount of distance from people while Navani needs an equal amount of intimacy. If the closest Jasnah can get and be comfortable will still make Navani feel rejected, and the most distance Navani can stand will still make Jasnah feel smothered, their relationship is pretty much doomed.

I don't think Jasnah's loathing for the thugs is really in need of an explanation. They're robbers, murderers and possibly rapists, which would be enough on it's own, and they were also preferentially targeting women of her class. With all that to begin with personal trauma would just be gravy. If anything needs explanation it would be her attitude to seduction. In WoR she equates seduction to rape and genders them as female and male respectively. While Jasnah's actual opinions of gender aren't clear (she's written an essay decrying gender roles that Shallan reads in a flashback, but judging by Wit's reaction to her wearing a glove in the epilogue she seems to be more attached to Vorin notions of modesty than Navani is) that's a pretty strange stance to take by any measure. It would seem more reasonable to guess at a bad experience with a woman than with a man.

It depends on how the extra stormlight cost from the honorblades works. It could be: a) having an active honorblade passively drains stormlight. Szeth uses x stormlight to use his surges and y stormlight per second while his blade is out. Two honorblades would drain 2y per second. using surges through honorblades is more expensive than using them through Nahel bonds. Kaladin spends x stormlight to use his surges, Szeth spends xy stormlight to do the same, where y > 1. c) holding stormlight with a honorblade bond is less efficient than with a Nahel bond. Kaladin uses x stormlight to use his surges and loses z stormlight (or z% or his current stormlight) per second through inefficiency. Szeth uses x stormlight to use his surges and loses zy stormlight per second through inefficiency, where y > 1. Jasnah gets Jezrien's honorblade and uses windrunner surges, spending x stormlight and losing z stormlight through inefficiency.

Jasnah is nearly symmetrical. So is Navani, although she's a Kholin by marriage. Possibly the Kholins have their own family tradition and Jasnah was named according to her mother's tradition?

Fire is an essence, and so is presumably easier and possibly less expensive in terms of stormlight. Jasnah also defaults to a ruby, smokestone and diamond in her soulcaster; to create ink and keep up the pretence of it being real she'd need to swap the gems out. Less bother to get creative with fire.

Not necessarily. According to Navani's message to Jasnah broken soulcasters usually have the gem housings out of alignment: they're warped, not damaged. The actual functioning parts seem to be a black box.

She also gets a paragraph or two in both books of drooling over Jasnah.

I do the same thing.

They also let you use surges without being chosen by a spren and upholding an order's oaths. Szeth certainly wasn't doing much protecting or leading.

That's pretty much it. Shallan's psyche is about 50% repression and denial. If she admits to herself that her shardblade isn't ordinary, she can't keep herself from thinking about why.

Isn't that how she does her super-climbing?

Yes. Always. Or as a very distanct second, Rysn.