It's a very long post, but a lot of it is a detailed discussion of terminology in the appendix -- no need to read that unless you're into definitional struggles.
Yep. And that's far from the only way it could work out badly. I talk about this a bit in the section on "Bluesky is a useful counterweight to Threads"
Bluesky is far from perfect. They're venture-funded, so likely to end with an exploitative business model. They've got a surveillance-capitalism friendly all-public architecture. It's great that Jack Dorsey's no longer on the board but he was.
This is straight up misinformation, Dorsey was on the Bluesky's board, but left in May. As far as I'm aware, he's never even invested in the company (but he has given money to the nostr devs).
It did originate from Twitter. Somehow Twitter at the time considered it wise to split it into a separate entity, and Dorsey was fine with not controlling it. And then Twitter was sold, and Dorsey and Bluesky grew apart from each other.
Correct. Dorsey's early involvement is certainly grounds for concern -- the way I think of it, he's gone now but his stench lingers on -- but he's not influential there going forward.