@jaytkay
“My animal list in the original question is from Michigan (upper and lower peninsulas), Southern California mountains, Los Angeles, Chicago (we have coyotes), Colorado front range and up along the Colorado, South Platte and Poudre rivers.”
Red foxes are pretty scarce in some of those areas.
Southern CA and L.A. have gray foxes. I think I’ve seen three or four in all my years here, although my boss had a den in her garden one year and got to watch the kits grow up :>) There are reds in CA, but they are only native to the Sierras and the Sacramento Valley; the others are descendants of escaped fur-farm foxes. Last I heard, they had spread as far south as Orange County, but I don’t think they are particularly common.
As far as Colorado, they are mainly found in the forest edges and riparian areas.
Michigan is pretty good fox country, especially in the areas with patches of wood and farmland.
You mentioned coyotes. In areas where you have both foxes and coyotes, the coyotes will kill or drive off the foxes. The foxes tend to live in the “no mans land” between coyote territories.
In many areas, foxes are also hit very hard by diseases like mange and distemper.
Good luck in your foxwatching. One of my life goals is to see a red fox in the wild (or at least capture one on my trail camera!)...at least when we move from San Diego to the Pacific Northwest it will be possible!