Since this is a bit complicated, here are some optional hints:
Hint 1: none of the thematic across clues mentioned above have cross-references.
Hint 2: however, some of them are cross-referenced by other clues.
Hint 3: you’ve probably already seen the word that gets removed from those down entries today.
Hint 4: those down entries are placed in the grid symmetrically.
Hint 5: the thematic word that gets revealed appears on a diagonal.