I'll keep the answers brief to avoid undo spoilerage.
For favored enemy Humanoid(goblin) is a good first pick.
For favored terrain, Underground is by far the best pick.
Of course if you spend alot of time outside the dungeon itself Forest would probably suit you well.
The Goblins AC and HP are too low to care about.
Undead and construct have DR or hardness.
Race think about Dwarf.
+1 to hit goblins and Dark vision
If can use traits try this.
Brigand [Link]
Source Kingmaker Player's Guide pg. 10
Requirement(s) Kingmaker
You hail from the River Kingdoms or the more lawless reaches of Brevoy. Life has been hard for you. Perhaps your parents and siblings were crooks and con artists, or maybe your rough, lonely life lead you to fall in with thieves and worse. You know how to ambush travelers, bully traders, avoid the law, and camp where no one might find you. Recently, you’ve run into some trouble, either with the law or with other bandits, and you’re looking to get away to somewhere no one would ever think to look for you. An expedition into the rugged wilderness seems like a perfect way to lie low until the trouble blows over. You begin the campaign with an extra 100 gp in ill-gotten gains. You also gain a +1 trait bonus on Bluff, Diplomacy, Intimidate, and Sense Motive checks when dealing with brigands, thieves, bandits, and their ilk.
It kind of fits the lawless of area.