Always expect the funny twist on a Thursday, right? When I could think of nothing to fit into 21A: "Miss Manners," for one, I knew something was up.
In fact, I got the revealer very quickly. It helped to know VAN Cliburn, the first American pianist to win the prestigious Tchaikovsky competition in Russia in 1958, at the height of the Cold War. That led to NARY and ABLE, at which point I put BLizzard in at 44A: Winter driving hazard ... or a literal hint to four squares in this puzzle (BLACKICE). Well, I figured that out, and off we went.
Despite my recognition that something was up, I didn't actually look back at the NW corner. The first rebus square I found was at 66A: 11/11 (ARMIST[ICE]DAY). It's not actually a requirement nowadays that any standalone section of white squares be clued separately. We've seen a number of puzzles where the second portion of an answer is clued by "-". In this case, however, it's fun that each answer following one of the rebus black squares is clued independently.
The other three black squares are symmetrically placed. ADV[ICE]COLUMN and POL[ICE]VAN are well done. I also liked SERV[ICE]DOG and NOD[ICE]. The last set is a little more problematic, if we're being nitpicky (and really, what else is the point of these reviews, I ask you?). I don't really like [ICE]AGE, because the rebus square is not encompassed in a larger word and simply reiterates the meaning of the revealer. Second, 64D: Time's partner, informally (TEMP) is a big huh? for me. Is "time and temperature" a widely used phrase? I thought of "time will tell", "time and date", and "time and space" first. Certainly nobody would ever say "time and temp", right?
In other news, I enjoyed many of the bonus answers here. LILABNER is nice to see in his complete name form. I also like CATARACT, MONGOOSE, and ODORLESS, which will always remind me of The Princess Bride ("What you do not smell is iocaine powder..."). YSHAPE is also great looking in the grid.
Not as big a fan of BARCARTS. I think we call them drink carts nowadays.
1A: Harsh cries (YAWPS) - A-. Walt Whitman. Nice. "I sound my barbaric yawp over the roofs of the world."
Fave: ENNIO (69A: Film composer Morricone). Amazing scores for The Mission and Cinema Paradiso, certain famous spaghetti westerns, along with scores of others (see what I did there?). Also, this answer enabled a foothold into the SW isolated corner.
Least fave: OSOLE (17A: "____ Mio"). This old chestnut partial.