I think any pre and post production use of AI doesn't need to be disclosed (which looks to be everything but (1) and (4)). Although, if I were to ask a friend for production help, I'd cite them out of courtesy and you could argue we owe that to the LLM researchers.

My line is when you begin copy and pasting things from LLM output as if it's your own work unless it's something formatting related like make this list a markdown list. I just see it as dishonest to share thoughts/content where it's assumed to be from your own brain when it isn't from your own brain and not disclose it. I read most things knowing that I'm taking an attention-risk and that calculation is affected by how much attention-cost the writer paid to produce a work.

As you say, this may just be where norms are currently. Eventually, maybe no one will think their own thoughts and produce their own content beyond the prompt and there won't be this mismatch of expectations. Instead, real writers will disclose the tools they didn't use.