Thank, Buddy. I had a smile at the "web-based foodies" and "the first sign of Big-foot"
I thought I was off to a flying start with group 9, but groups 3 and 4 were a bit more tricky.
I still don't see 26d. I have U?NE
It ceased publication in 2019 and there are no articles on its web site dated after 2021, so it appears to be defunct, living on only in the occasional NYT or WSJ crossword answer. So rather than GK it is CK (crossword knowledge).
The New Yorker recently ran a cartoon called A Crossword Odyssey about such words: