From what I learned from Yann and others, none of 
those are genga. All are production sketches, 
yes, but not genga.

(Let's see if Misha can remember her correct 
definition)

A genga is a drawing done by a higher up animator 
to show certain aspects of the characters for 
that scene. It's a loose guideline for the 
animators, and one genga can be used for a good 
chunk of a scene. It is removed altogether from 
the production process in the fact that it does 
not do any of the actual production of the anime.

i.e. if I took a picture Kazuya Minekura drew and 
used it to help me understand how to draw the 
Saiyuki characters, and thus drew my own 
independant fanarts from that, that type of 
thing. (not saying that would be a genga, just 
trying to explain how a genga is roughly used and 
not actually part of the process itself)

As for the sketches, I have seen a few cels that 
got them all. I myself have a cel of Mama from 
Tennimon that. Many people who collect sketches 
have sets like this (though it is harder to get 
sets like this with cels), and it's not a 
something done and distributed solely by Sunrise 
(as you can see, because my Tennimon sketches are 
Pierrot).

Hope this helps!

-Misha-chan