It is a great piece of work. About the patches: I do it the almost the same way: draw alpha on top of the photo - create mesh from alpha and then manually sculpt on top. If alpha is good - less work is required to clean it up.
Here is the last one I created that way (more time spent on alpha, and did not touch it with sculpting tools at all - as this is good enough for really small piece of sculpt):
Now about the "competence", as You mentioned me in the post, I think You are just being modest, as this shows both technical and artistic skills that are great.
For example, I have no idea how you did shoelaces, so If this is not a secret, please share it with us