I think you've done a really good job, especially with the space you had and the limited (quantity, not quality) equipment you were working with. As a result, my suggestions for possible improvement are mostly going to be really nitpicky. And, of course, what is relevant depends on who is getting the photos. I don't know which of the young ladies is the daughter of the neighbour who commissioned the photographs.
The above photo is the only one I'm actually concerned about as far as the capturing of the photograph went. Their faces look a bit soft to me, especially hers. It looks like it may be a bit back focussed, but I can't tell for sure. It may be something that happened when the photo was uploaded to the website, or when you created the jpg/png for upload.
As far as post processing goes, I'm inclined to suggest trying to brighten the exposure on her face just a touch (using whatever technique you're most comfortable with).
As far as the pose goes, he almost looks like he might be a bit hunched over and leaning forward.
She look's a touch stiff, but I think he steals the show in this one. I love his pose, and how comfortable, confident, and naturally happy he looks. He might be worth hunting down to try some senior portraits of, if you want to try your hand at those. I suspect he'd be fun to work with and a great subject.
The separation between the subjects and the background looks a touch artificial to me in this one: mostly around their hair and along the outer edge of her arm. It might just be trickery from the light, shadows, and the wide aperture, but if it is something that was done in post it might be possible to lesson the separation and make it look a little more natural if you're so inclined.
I don't think we need to see the corner of her dress. We know what it looks like, and our brains can fill in the blanks just fine. I really like that you put the young lady in the red dress in the middle. I love the attitude in this one. I think the pose it great.
For seriously nitpicky stuff, the young lady in the red dress appears to have an unnatural looking dark spot at about 10 o'clock from her elbow joint. If it is isn't a natural feature of her skin I might try to clean it up a bit.
Depending on how much work you want to do to the photos and what you're comfortable playing with, you might like to try smoothing out the skin on the arms of the young lady in the red dress and the young lady with the darkest skin tone. Particularly the latter.
What a lovely photograph. I'd suggest trying to smooth out the red bumps on the arm closest to the camera a touch, and maybe try to clean up the hair that looks like it might be caught in her eyelash.
For additional suggestions (gear you didn't mention using, and might be worth playing with to decide if you want to use it in the future), a circular polarizer might have helped in reducing the glare on the young gent's glasses. A reflector might have been handy (if you even had room for it, which you might not have) for getting just a little more light on their faces and lessening some shadows (which are already pretty minimal, where they exist).
Very nice set. I think this is a great first attempt.
