I don't know why people discount tracing. Speaking as someone who's studied the subject, tracing isn't nearly as easy as it sounds. I mean, it's orders or magnitude easier than relying on direct observations, because translating what you see in three dimensions to be convincing in two dimensions is difficult.*
Fun fact: the camera obscura was used for tracing in ye olde days.
*It really does teach you how screwed up our visual system is, though.
As for these drawings: they are technically artful, and the redhead is particularly striking, but they seem kind of flat to me otherwise. I think it's cool that they were done in ballpoint pen, but they seem... yeah, flat is the best word, I think.