Excellent points. Here is what I think.

1.   beautifulness (why not beauty?) => I simply feel “beautifulness” echoes the first two “beautiful”, making a point there.

2.   inside and outside =>  We come back to this one when you know why it is wired.

3.   I liked to play vs. I liked playing =>  It is a personal choice. There is no difference in meaning.

4.   At (insert "the")beginning => yes, need a “the”

5.   “had left” to “left”=>  “had left” slightly emphasize consequence.

6.   half (insert "an") => yes, need “an” there. I guess I keep losing “an” when I speak the sentence.

7.   with top one’s peel neatly removed(not wrong, but I would use"with the top one neatly peeled") => I thought about that and then I decided to go an extra mile to emphasize.  Or maybe it is my imagination.  I saw such an expression in a novel, and thought the author must want to emphasize the effort being made.