I really like them as a whole, but I feel like the first image, of Keiyra, isn't your strongest work- her hair kind of lacks definition- I get that you were maybe trying to make the edges diffused and that these are probably quickish sketches, but it looks a little unfinished- it seems to lazy the richness of your usual work. Also her jaw looks like it is maybe a little too far forward? I think that might just be because the shadow on her bottom lip comes across a little too far to the left, maybe.
That being said, I am always really impressed at your ability not just in portraying different ethnicities, but in really creating seperate and distinct characters- a lot of semi-realism type artists seem to distinguish different characters with just slightly different noses or hair colours or something, but your faces are always so alive and distinctively individual that I can always see them as being real people, like getting a glimpse inside the living world of your imagination.
I'm always really hesitant to give critiques, as most people see them as being an insult or something, but I figured you would be able see it's more that I like your work enough to speak honestly! I wish I could get anything even half this finished in just 30 minutes.