Very nice pics. I really like the Barnevelder X. The one I have is darker so I think yours got the blue gene and mine didn't unless there is some other factor in play. I will try to post a pic soon but I am envious of those beautiful blue feathers that are coming out.
As for the Brahma X, it is very similar to the one my friend is growing(except the crest)and if I recall from the pics you posted of her at a day or so old, she looked almost exactly like this one in the middle left:
Now the middle left one grown up to look like this:
Yes they were chick twins! I wish mine got a crest but she is still gorgeous IMO. The Barnevelder X almost shimmers in the light 😊