> 1. Permanently take down nitter.net and the GitHub repository[...]

This is the one that they know they have absolutely no grounds to demand, which is why they started with it. Everything else can be conformed with without even really damaging Nitter (the project.)

> 4. Delete all X account credentials and session tokens

could be trouble for individual servers, but is on legally shaky ground, and servers can simply go down at the first strong challenge and open back up under another name. Nitter the project doesn't need to have any credentials or tokens.