Hint: It's interesting how those six quotes (i.e. 4-Downs) are symmetrically located in the grid.
Hint: It's also interesting how the first letters of those six quotes spell a certain generation of folks.
Hint: But the prompt says it's a 12-letter group, so 6 more letters are needed from somewhere.
Hint: Take another look at the peculiar beginnings of those 6 quote clues. Do those first letters spell anything?
Hint: Add this new 6-letter word to the previous 6-letter generation to get another generational term that applies to me.