I believe there rally are a FEW "Havana brow" Havanese. But they are EXTREMELY rare from what I've seen. I have yet to see a single dog that was "called" Havana brown as a puppy that actually grew up to be one. Every one that I know has either been "fading black" or some shade of silver... though some remain mostly black dogs with a few white hairs sprinkled in)
Kodi and Panda have both been blue-black from birth. They have never had any brown tinge to their black parts, nor do they have any white mixed into their black parts (Except that Panda has eyebrows, and Kodi has some white marks that are "scars" from tick bites)
MOST of the silver Havanese I know have gone through a "brownish" phase as adolescents.
But then... Pixel fooled us. She turned brownish, at just about the same time as Dee Dee's Sophie (they are both very close to the same age) Then both Pixel and Sophie developed some white hair mixed through their coats, and Pixel developed a splash of white behind one ear, and a wide white streak in her tail. Sophie, as Dee Dee has told you has gone on to become a darks silver on a lot of her body. Pixel, however has reverted, and is now as black asKodi, with NO white hair in her coat!!! Even the streak behind her ear and on her tail are gone!
The trouble with trying to figure a lot of this out is the we have genetic markers for only a few colors... And besides the base colors, Havanese also carry MANY "modifier" genes. And then "markings" can get in the way too. I THOUGHT Panda had "eyebrows" as a tiny puppy, but with the white on her face, you have to comb her hair JUST the right way to find them... and I wasn't sure. But we had her genetically tested for color, and she is "AT/AT", which means "points" (or eyebrows) so I DIDN'T imagine it... her white markings just confuse the issue.
So black can be "covered" by one or more copies of the silver gene... and there is also whatever gene makes "fading black", though we don't know exactly what that gene is.
There are only a couple of colors that will disqualify Havanese in the show ring (blue or merle) so few breeders bother to test for color. However, some breeders purposely avoid chocolate (because it's very hard to consistently produce chocolates with good pigment and eye color) while others purposely breed FOR chocolate (because so many pet people go crazy for them). Breed chocolate to chocolate, and you will, for sure get chocolate. But you also risk poor pigment. Breed clear red to clear red, and, again, for sure you will get puppies somewhere along the continuum from cream to dark red. But red sables are a lot more complicated in terms of their genetics. Different combinations of genes can come up with dogs that appear to the eye to be very similar "red sables". So more people do test for chocolate, and because reds have become so popular, and are tricky to reproduce, the breeders interested in breeding red dogs, or adding red to their lines are also more likely to color test.
As for all the rest? That's one of the charminging things about Havanese. It's hard to know, for sure, what you'll end up with!