In Blood Meridian, two of the more striking images during the Comanche attack are a warrior wearing a wedding dress and one wearing a top hat and carrying a parasol. The following are the probable inspirations. The 1st is Dakota chief "Little Crow" wearing a wedding dress:
Apparently, "Little Crow" wore this wedding dress often. In Blood Meridian it is described as being spattered with blood, likely a reference to scalphunter John Joel Glanton, whose fiance was murdered by Apaches.
While we're on the topic of "Little Crow" he supported the Dakota War of 1862 resting in 38 Dakota Natives being order hanged by Lincoln. In 1868, there was a show in St. Paul called The Panorama of the Indian Massacre of 1862 and the Black Hills...
The show was a series of paintings of brutal scenes of the war, leading up to, and trying to justify, the hangings. One of the paintings was called Minnesota Fruit and in lieu of apples it depicted white babies in trees, possibly the inspiration for McCarthy's Tree of Dead Babies
As for the top hatted man with the parasol, in the 1890 book Indian Depredations in Texas by J. W. Wilbarger there is this woodcut by TJ Owen, a pseudonym for William Sydney Porter, more famously known as O. Henry...
You can read about this book and see more of O. Henry's woodcuts at https://www.tsl.texas.gov/exhibits/indian/early/page3.html