This accomplishes exactly what was asked from you for this assignment. Let’s begin by going through each photograph.
Your first image shows a bride in the spotlight of the sun. The composition is back-lit and the sun is creating a beautiful highlight around the edges of your subject (I love how the shadows wrap around the brides arms). Backlighting is often more difficult to use because of exposure issues, but you’ve managed to not to lose any detail in your main subject by keeping the light source high enough. This allowed you to properly expose your foreground subject. If the light was lower you would have had to make a big technical compromise. Either you would need to “burn out” the sun and surrounding area (loosing all detail as the tones stretched into the bright whites), or underexpose the foreground subject by pushing your mid-tones into unidentifiable dark tones. What you’ve accomplished with this image is rare because you have such a small window of time to play with light at this direction. Great work.
Your second image is maybe my favourite of them all. You’re right that you’re subject is cast in soft light (shaded by either a cloud or a tree), but you still have a nice hard light highlight in the background that adds some tonal depth to the image as well. This image has very thoughtful place, great color control, beautiful shapes and lots of texture. Again; great work.
Your last image is the most gently lit photograph of them all. You have no lighting highlight in this image and no lighting source can really be identified. The light is diffused and scattered and therefore evenly wraps around your subject.
Overall, this is a beautiful assignment.