On inspection it turned out that only one question had that misspelled tag. I therefor submitted an edit so the tag was no longer used on any question. Once the edit was reviewed and approved there were zero questions with the misspelled tag.
After 03:00 UTC the system runs a cleanup batch to remove so called "zombie" tags.
The timing of all actions was ...
Agreed. The color of the text is #AAAAAA. On a white background it doesn't pass WCAG AA compliance. Contrast ratio is far too low. See this screenshot taken from snook.ca
It'll be much better at #545454 or even darker:
I've looked over a bunch of other StackExchange sites and none of the ones I checked have such a feint colour for the search field text.
Yes, although a minor point I would probably agree. It's less of an issue for people with all three classes of badge because the order of the badges is always consistent (the same way that traffic lights aren't set in different shapes - we know the bottom one is always the green one), but in Stack Exchange world people can have one, two or all three types.
Yes, really they should. The only reason anyone would chose not to do so is for visual issues relating to readability - too many in-line links potentially slows down and impacts the site readability. This is probably the reason sites like Wikipedia take that approach.
However, adding underlines back in is likely to cause a few complaints. "Why are we trying ...