A few thoughts:
I've seen Tender Offers mentioned a few times in various articles, but I've always been curious about how such an event would affect the 409a valuation. Are Tender Offers usually closer to preferred or common pricing? Does it just depend on the company and that's why there's so few resources?
Also, I see liquidation preferences mentioned very very briefly, but in my opinion it's insanely important for prospective employees to get a sense of the cap table.
Also, if you're joining very early and a sought after talent, negotiating a longer post termination exercise window is doable, rather than the typical 90 days.
It's usually really hard to negotiate a longer post termination exercise window as an individual, as that will have to be written into the options plan (which requires board/investor majority approval and is generally a huge legal doc written before). However a lot of strong startups these days are offering all employees with longer (e.g. >2 years) experience the opportunity to exercise for 3+ years and sometimes significantly longer.
https://github.com/holman/extended-exercise-windows is a good resource!