2) For what it's worth, the Twitter employees let go were not just programmers, but also fulfilled other roles. I'm not quite sure what percentage of programmers Twitter lost, but I bet they lost a much higher percentage of other roles such as HR and content moderators.
> BTW. Figuring it who is the core team is not that complicated. You just ask everybody to name five people who are doing well and who they want to work with again (in the next company).
For what it's worth, this might yield a misleading answer because it could become a popularity contest.
The charismatic guy who plays office politics and tries to make everybody their pal might score highly here, but the smart engineer who just sits down quietly and churns out good features might be forgotten.