@luka I'm not sure I understand that question. You were looking for description of the early history of Mastodon, right? This isn't the earliest but it's an important chapter because it covers much of the network's growth.
You mention having heard about "origins in queer/trans furry #poc circles" but it appears to me that that is mostly a fairy tale - there are some interesting minorities in English-speaking Mastodon but they cannot properly be called the originators or "progenitors" of it.