Even more for babies, facial muscles make all the face look different when eyes are open or closed. Maybe he can but he thinks that it wouldn’t look right, reworking a whole face is immediately a lot harder.

For me that’s capturing special moments, interactions or views in urban environments to tell a story through the photo.

Is it random pictures of strangers?

It can be, but it needs to have a story, something special in the interaction or the environment, I don’t consider that guys taking photos of young women in the street without consent just because “they are beautiful” is street photography (but weirdly that’s one of the most popular photo style on social medias…)

These two words have connotations but they can be used to define the same thing. A selfie would be for most people a photo taken with the smartphone/camera in your hand or on a stick, while a self portrait would be a photo with a dedicated camera on a tripod.

Also the “obvious skill difference” that you talk about comes from the photographer, not from the way they call their shooting style ;)