The Yarrow was north of Crested Butte, Co on the Schofield Pass and the Pearly Everlasting was in the Glacier National Park in Montana. I think you've hit the nail on the head with your identification.
At Joshua Tree National Park, Great Basin langloisia aka lilac sunbonnet, langloisia setosissima. Note the spiny points on the bristly leaves. The pretty white hued flowers below are desert star, monoptilon belloides.
...And then a bit further along the trail saw the above strong subject so again spent a few minutes getting a set of shots in. In the foreground of the above image is great red paintbrush, castellija miniata, and luckily given breeze blocking trees, managed to get 15 shots off during a couple minutes with reasonable still air. The species has considerable variation of color and this particular plant was a less common wonderful rose pink. There are a list of paintbrush species with leaves a key necessary for identification and these leaves were distinctively narrow leaves with smooth edges and an acute tip of this most common species. Complementing the frame were some mule ears, silver lupine, and bunch grass plus further back an aspen trunk, big sagebrush, and red hued paintbrush.
...A bit further south on the trail one enters jungle like wildflower growth with vegetation at waist to chest height. Right at the edge of the trail I stopped when I saw the above wonderful subject. Of the hundreds of people passing by, it was obvious I was the only one to work it as I needed to bend a few for-get-me-not stems in front of it out of the way temporarily for a clear view. These seep loving species are wavy-leaved paintbrush, castilleja applegatei, and broadleaf lupine, lupinus polyphyllus, plus the one yampah. Note the wavy leaf edges of the paintbrush. As the landscape above east on Elephants Back was still shadowed, it causes a slight varying night time cool air flow down slopes that jitterred leaves and flowers slightly.