1) Minimalism in photography includes color, shape, line, and texture. The minimalism is an art movement. The qualities that the minimalist photographs possesses are in the image something should catch the eye of the audience and the rest of the image should just be one simple color.
2)

This image is using a solid color and pattern. Using the color yellow for the background the focus goes right to the green leaf.

This image creates a lonely mood. I would say this subject is a young girl who sits by herself cause she doesn't have anyone to talk to and friends.

This image uses a dark color background of orange and focuses on the man walking. It appears that he is all by himself and walking himself on a long journey.