I asked my mom about the red thing and here's what she said:
Now, about red at a wedding: I wore a red dress once, and looked around to see if I were the only one that did; I was, so I haven't since, although I have seen both white and black, which I thought were more taboo than red.
My advice is that in Santa Fe, anything goes; you are no longer in the Deep South, with "your mama and them" looking you over.
This only deepens my confusion and alarm. (There's nothing worse than feeling as though the disembodied spirits of your mama and them are looking you over; see diamond entry below.) Solution: Wear an old and respectable dress, and spend dress money on spa treatments to achieve Inner Glow.