@dynamic most of that seems correct. Though, you say "Fedi protocols" and when I use the term Fedi, it's short for Fediverse and that is specifically the nickname for ActivityPub. If a protocol doesn't connect to ActivityPub directly, it's not the Fediverse. Those protocols do connect, but that's because they had to change to do so when AP became more popular. BlueSky isn't and probably won't be Fediverse, just bridged to the Fediverse.
Also, BlueSky isn't all one big instance. Here's a detailed explanation of bluesky that I wrote earlier today. It's long, but very detailed.