Late August in the Kaibab National Forest (North Rim of the Grand Canyon). So what are the yellow and white flowers? Have an idea for the white ones but I am stumped by the yellow ones.
White-pink looks like Erigeron karvinskianus Yellow could be Helianthus sp. or Heliopsis sp, difficult to say, the picture is quite blurry when enlarged.
Erigeron karvinskianus and Heliopsis sp. are not found around the Grand Canyon. All Helianti I know are with larger leaves and/or with dark disks.
Yes, I am leaning towards your id of the yellow flowers. Still, the Erigeron looks more like Erigeron karvinskianus in growth habit, leaves, and flowers, than like any of the other species proposed here.