[gasbag]

That's a good list. I'm curious about what you're referring to in 6. The only thing I can think of is beneath Nessus, but I can't for the life of me recall how it plays into what Severian writes (or perhaps rather what he doesn't). It's been a few long years since I was last there though.

[observation]

I'm rereading now and have spotted a third example: <spoiler alert>

Severian describes how Master Gurloes is an educated man and that he talks to other people/beings through something like a radio network at the top of the Tower.

It was phrased like this:

"He was the only one of our guild - Master Palaemon not excepted - who was unafraid of the energies there and the unseen mouths who spoke sometimes to human beings and sometimes to other mouths in other towers and keeps."

[observation]

Possible spoiler alert: Can think of two examples.

I am readying myself for a reread (including Urth, as yet unread), so this is all IIRC, but there is a paragraph mentioning how Erebus or Abaia have influence in the world - likely through a computer network similar to the Internet (as telegraph to Net, Net to ...) but unimaginably more sophisticated e.g. embedded into everything, like the IoT. Of course there are other entities with access to infrastructure that the peasants are either ignorant of or dimly aware of e.g. cacogens, Father Inire.

Another example is Jonas's past life as a sailor. I believe at first he is a sailor, but later... very poetic.

The bit that is bugging me about BOTNS is part of the final book, where a young woman is seen by Sevarian in an old part of the city - it's beautifully written and this feels familiar but I can't place it, I know there's something I'm missing about that experience.

That has settled it, next time I take notes ;-)

Great moments for me include:

Sevarian's explanation of his craft's morality (which he later discounts!) The battle of the flowers. I could see it. Realizing Agia's betrayal. Rethinking everything I've read after the gemstone, and then again after the nature of Sevarian's role is uncovered, and again as I realize the meaning of a Autarch. The Ascians! So much more. Often I'll realize something about it hours or days later after reading.

Note: if you read this past the spoiler alert, do not be afraid, read the book!