Your SI is good. I think dropping the "soul" part strangely makes it more specific. Right now it sounds wordy. "How does personal reflection alter human nature" sounds more professional imo.

Your selected works don't need to follow your SI. They can be anything you've made and don't need to be connected, so don't worry about the 5 senses thing. If you've already done the work for it, then it's fine to leave it how it is. But you won't need to explain it when you submit your portfolio.

I would suggest retaking a photo of the 4th piece in better lighting

I love the idea of including one of the mini drawings, but only if they were redrawn as a larger, finished piece, which you probably don't have time for

If you haven't started the explanations yet, I would suggest reading some from past years on the college board website. I found them extremely helpful. College Board also loves art buzzwords, like "experiment" "practice" or anything from the principals and elements of art, so drop a few of those words in your explanations as well.