Crossword puzzle clue "like the squares that comprise this puzzle's special letters"

Like the squares that comprise this puzzle's special letters

Party staple suggested by connecting this puzzle's special squares

1866 debut, and a hint to the pattern created by the puzzle's special squares

This puzzle's special squares, e.g.

What's revealed by connecting the special squares in this puzzle in order

Fashion runway, or, in a way, what this puzzle's 10 perimeter answers comprise

Legislation signed 6/22/1944 by FDR ... and, initially, what the nine longest across answers in this puzzle comprise

School's underclass team ... or, initially, what the four longest answers in this puzzle comprise