Hint: There are several wacky, probably never-before-seen, entries in this grid.
Hint: These 6 symmetrically-placed entries all seem to be close to spelling something else.
Hint: Actually, with the addition of one letter each, those 6 entries can…
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…
Here is a link to the solution on the XWord Muggles site: https://www.xword-muggles.com/viewtopic.php?p=146591#p146800