"Creature design would be based upon the following:"
"Three-foot-tall humanoid (as in two arms, two legs, upright) form that has been infused with the draconic essence of a god.”
I don’t like the “Infusion of draconic essence”; they are not lesser cousins of the dragonborn, but perhaps a reptilian race with delusions of grandeur.
I never cared for creatures under 4’ as they are nothing more than ankle-biters. At 3’ the kobold is the equivalent of an “average size boy” of the whopping age of 2 and a half, I’d prefer to be attacked by kindergarteners or 1st graders instead (i.e. < 48 inches).
“Slight skeletal frame.”
Disagree here they should have an “average” skeletal frame as they are a warlike race capable of attacking or defending themselves against beings of equal size (e.g. gnomes). The Dragonshield would look awfully humorous (much like the Tiny Warrior from Ace Ventura: When Nature Calls).
“More about intelligence and agility than strength or brute force.”
Against larger creatures and their traditional enemies (e.g. small fey) they need to develop both, but again I think an average strength is sufficient. The race is noted for having individuals of great intelligence (i.e. the alchemist).
“Furtive and cowardly alone, but ferocious and dangerous in a crowd. This would drive all major design decisions.”
I would prefer stealthy and cunning when alone, a master of improvised traps and bushcraft (e.g. MacGyver or Dutch from Predator). Again as a warlike race a group is always more dangerous than one.
“Hairless, scaly hides that range from dark brown to black.”
More specifically an earth tone scheme are muted and flat in an emulation of the natural colors found in dirt, moss, trees and rocks. Many earth tones originate from clay earth pigments, such as umber, ochre, and sienna.
“Large intelligent eyes that are suited to life underground.”
More like cat eyes (including shades too) suitable for night time raids (not darkvision, but low-light).
“A long tail (prehensile) that integrates with the rest of the body.”
Again like a cat, the tail is used for balance and agile movement. But absolutely not prehensile, they are not monkeys or opossums!
“Hands that are quite deft and capable of intricate actions. This would also indicate an ability to craft and make culturally appropriate clothing and accessories—perhaps draconic in theme? “
As an intelligent race they should have the ability to craft items suitable to their environs and culture. 1E had them using wicker shields, swords, axes, javelins and spears – so did many of the ancient Mediterranean and Middle Eastern cultures.
It should also be noted that they are capable of taming wild boars and giant weasels as guardians, which considering RW boars is no small feat.
“Affinity to, and reverence of, dragons.”
As stated earlier they have issues and claims of dragon-blood running through their veins makes them feel better. A social order and worship based on admiration of draconic traits and service to infamous dragons would be a way of proving their claim of kinship.
The dragons don’t mind the cannon fodder and no sane enemy would think of them as cowards, especially if they have no clue if a dragon is around or not.
“Small white or beige horns.”
This is a whole different can of worms without more details
Age was not a factor listed by you, but the kobold’s lifespan of 135 years and their lairs having up to ~640 individuals and 300 eggs indicate a race of survivors.
Habitat was also not factored, while Mr. Wyatt claims when they cannot live near dragons, they live like rats in warrens. I prefer the original idea where they live “in dank, dark places such as dismal overgrown forest or subterranean settings”, which considering their hatred of the fey creatures (e.g. brownies, pixies, sprites, and gnomes) gives the kobold a wider range of artistic possibilities.
Also will there be a definitive artistic difference between male and female kobolds?
IMHO kobolds should be a feared adversary and not the Jar Jar Binks of D&D!!