Fantastic! I particularly like the last one. My feedback would be on the 3rd image - I think the hair and shadow is a little separated from the face and might benefit from some hairline work or shade (particularly on the left side of the face (her right side I guess!))

I did these charcoal (some ink) drawings ref'd from Bargue plates a while back. CC always welcome.

I know that we are supposed to critique each other, but, to be honest, I love these portraits. Specially the first one. Maybe, I can say that you need to refine the technique more, so the result could be crispier, but, I don't know enough about the medium to be critiquing it.

Note - It's not that I drew all the sketches in <1 hour. I wanted to say, it took me less than an hour to draw each sketch. Sorry for the miscommunication.

Those are very well done, it’s amazing that you could do them all in just an hour! The first woman looks like the might have a secret with her little mona lisa smile and I really like how twinkling her eyes look! Though the right eye (her left eye) look maybe a tiny bit to big in comparison with the left one and the corner of the eyes closest to the nose looks a bit off to me in how they align with each other. So I think the eyes might look even better if you were to make the right eye a little smaller and tilt the angle of it’s tear duct a little bit upwards In the second female portrait, there are such soft emotions on her face, she seems like she is daydreaming. It’s truly beautifully! There is emotion and personality in all of your drawings. I see it the most in the female portraits, but also in the male ones and I like them to. The first man looks so very kind, while the second looks more mysterious and the different drawing technique suits that mysteriousness well!

They are all really good I think and I don't have much expertise with portraits, so here i just an idea. In the first three drawing the lines are obvious and if you use them very concious they can be a great style effect. But i think right now you do not control too much where which line shows how clearly. For example in the second drawing one ear is really clearly lined out the other has no lines at all. And it migth be interesting to try to form all the edges without actual lines as a practice. I think that would take more time though. But I really like the effect, how you use limited lines. The fourth one is different obviously, I am only referring to the frist three. But the style of this last one is also very appealing!