To be fair, IMO that's actually a synonym of "actually". :-)

I'd say no. I'd say you're going too far to always assume that any starting phrase is always natter. It's a good rule of thumb, but sometimes those phrases are used to help explain the previous point. While they arguably need to be rephrased, they do not need to be outright deleted.

I'd also say that not all jokes are natter. There are plenty of times where humor is appropriate. I'd actually like to see a page devoted to knowing when that is, rather than lumping it all here.

The way to tell if something is natter is whether it responds to the previous point as if they were talking to them. Or if they are encouraging responses. To be conversation, there has to be an element of actual conversing between two or more contributors.

Examples Are Not Arguable

It appears that way to me too; as "didn?'!'?" rather than "didn't!" The original source isn't typoed, just here.

Then I'm fixing it.

Edit: Wait- never mind. Looks like I can't. Guess we'll have to wait.

Though that would go against the purpose of the page.

"Self-demonstration"ness in this page is already covered by Thread Mode.

No. Never has been, never will be.

Good, then it's time to begin the purification.