No April Fools need apply

Here are the latest crop of you-know-whats¹:

What is Moscow?
What is Catfish Row?
What is incontrovertible?
Who is George Burns?
What is a demon?
What is Vertigo?
What is Malachi?

In the category Russian History, the clue was "Ivan I lived in this city."

In the category Seafood Scenery, the clue was "the waterfront marketplace area where Porgy and Bess lived."

In the category 16-letter Words, the clue was "the kind of evidence that cannot be dismissed."

In the category People Who Lived Past 100, the clue was "this man co-starred in 'The Sunshine Boys' and left without saying 'Good night, Gracie'."

I cannot remember the fifth category or the clue.

In the category The Movies, the clue mentioned Kim Novak and James Stewart.

In the category The Old Testament, the clue mentioned "the last book."

¹A you-know-what is the term I have decided to apply to an answer no contestant on Jeopardy! came up with buzzed in on knew but which I was yelling at my television set.