Take the "extra" gear with you.
Things change fast, and there is no penalty for leaving it in the car. Wishing you Had brought it, on the other hand...
To your gear list I would add -
-Bandana or some sort of nose wipe
I don't think you will need the -
-Trash compactor pack liner (unless rain is possible)
-Dri Ducks (unless a Lot of rain is possible)
-Map or Compass. It's literally straightforward. At most, take your ETAs & Mileage for the Tonto, Phantom, Cottonwood, and North Rim,... and back.
I assume the Marmot Ion serves as a very breathable windshirt?
Weather status can be found Here.
The area of interest is the pink box. You can zoom, click, and bookmark to define locations for the South Rim, North Rim, and Phantom. (This target is the Tonto/Kaibab Junction.) By watching it over the next two weeks you'll have a good idea of what to expect. I see that tonight the low on the North Rim is expected to be 45°F.