That’s a lot of feedback! Thanks you very much for taking the time to give me this feedback, it is very much appreciated!
@Griffin-McPherson yes I have tried multiple designs for the stepmother. She is meant to be mystical, magical, manipulative and threatening. Her hair breaks her human, seductive silouhette with threatening random spikes, while still making a high contrast frame for her face. So it might not be perfect, but I like it 
@carlianne that’s funny because I wanted the dad to also look rather normal. Only the stepmother and witch are meant to look unusual.
In terms of the kids being ugly.
Concerning Gretel, I have changed a little bit her design now, so she doesn’t have a snotty nose and she has cuter eyes. My initial idea was to give her some Tim Burton-esque eyes (small dots) to make her look a bit creepy, as she is going to kill a witch in cold blood in the story. But I guess I can change her eyes during the story, when she is on the way to snap.
Portfolio piece 2/15

Concerning Hansel, note that I already reviewed his proportion and changed his design when I’ve worked on porfolio piece 1. He was much more ugly initially, with black ring under his eyes from lack of sleep.
Here is how Hansel looked like before:
(note the « new design » is an old one)
So all in all, in porfolio piece 1 I already brought his eyes closer to his nose (to answer @kayleenartlover and @kirsten-mcg ). What I’ve tried in the following turnaround is to give him rounder cheeks and slightly wider pupils.
Portfolio piece 3/15

Generally speaking, I want the kids to not be over designed, and just serve as vessel for the story. I wanted to make them look poor and not well looked after, but I stepped back a lot from that idea. Only the fabric patches and holes in Hansel clothes remain as a clue.
@kayleenartlover concerning the « modern tale » bit, I may change that subtitle. The thing is that I use the script given by Jake, Will, and Lee in the CBP course. I did not want to make any changes to the script, and just play with how much the illustration can deviates from the traditional interpretation of the text. For instance, in the script there is nothing told about the stepmother being a magical being that manipulates the dad with some sort of magical mind control. But I add this idea in the visual story telling and I try to hint to that the witch is the stepmother. She is a sort of parasite that zombifies lonely Dads and eat their kids.
And you are right, Hansel and Gretel is a grim story and so it is hard to sell it as a Children Book to be honest. Maybe a children book for 12+? But anyway
here it just serves as a good opportunity to make portfolio pieces.