I am writing a story about a scenario where about 12,000 Americans are dropped onto an alien planet, specifically in a desert region of the aforementioned planet. Because of handwavium, they all survived and gathered into one place, called New Washington. By way of magically accelerated evolution, all of them become adapted for desert life within one year, and actually survive it.
I'd like to know any physical differences between these Desert humans and regular ones. However, rules for the evolution are as follows:
They must remain human-like. As in, they give birth to live young, feed them on milk, and have hair at least on their heads (Facial, eyelash, genital, and other hair can go away for all I care). In addition, they must have some hair and eye color variation (Like blue and gray eyes, or red and black hair).
However, internal processes can be different, except for reproduction. Give them heat resistance, better sweating, and anything good for desert survival, particularly things that help them retain water.
The planet's system is this:
Two K8V stars at the center, orbiting each other at the distance of Mercury and the Sun.
The planet orbits at the most habitable region for these stars, while orbiting both of them.
There is a gas giant 4 times heavier then Jupiter some ways away from the planet, keeping pesky asteroids away.
The planet has one Titan-sized moon, and is otherwise identical to Earth.
The desert region has numerous rivers and a number of saltwater lakes, and is between mountains and a sealine.
What would these humans look like after the evolution is complete?