So here are some things the Top Hat clue could refer to.
- Magician. (No, don't want a magician season, too close to Freak Show)
- Capitalism theme (A Top Hat was seen in the past as a symbol of Capitalism and being of Upper class)
- Uncle Sam (Army/War theme. Ethel did mention Soldiers.)
- Abraham Lincoln (Idk maybe it takes place in the 1800's, that's when top hats were most popular)
I do think it leans more towards the side of Politics as a theme though. A lot of Presidents wore those, and they were symbols for J.F.K. So I think a Political/Capitalism theme is quite likely.