That is entirely possible. I would think that a Goblin kingdom would be mostly focused in the mountains or on the slopes that divide mountains from flatlands. They would inhabit caverns though, and their cities would be based in large tunneled out sections of mountains.
Human economy is centered around livestock, horses, and the growing of wheat, brewing of beer, and growing of vegetables and some fruits. So on the domestic side, you can expect that chickens, cows, and horses will be involved when you are Human. Humans are mostly farmers, Dwarves are miners, Elvish economy is centered around rare herbs and spices (medicines).
Goblins would mostly be miners as well, and while physically somewhat weak because they are small creatures, they are probably, alongside Dark Elves, the most intelligent chaotic race. I was thinking Goblins can be sneaky, and thus are good at spying. Goblins have great defenses as well because of their mountain dwellings, but you will have to deal with Dwarves. The thing about Goblins is that they are great at metal-working despite their small size, because they have access to many raw precious materials. A Goblin kingdom would be a network of tunnels going through the mountains with large caverns and towns tunneled into them.
Other animals you can expect are Centaurs, probably the most intelligent of the animals, but not intelligent enough to form civilization. You will find large birds, such as gryphons, sea monsters, lake monsters, various types of monsters, rare monsters that you can get rewards for killing and that may attack you. There are barbarians, and there are elephants found in jungle areas. Dragons still survive somewhat, but they are extremely rare, as most of the living ones are enslaved by the two ancient civilizations.
I'm still drawing the map. What I can tell you is that the map is made of hexes, and that is how movements will be done.