Given the monstrous attacks of late, just wondering what the current attitude of the merchants in lower (Speckard, Mikkelsons, etc) are toward any kobolds or goblins that seek to buy/sell from them?

Other than it's a deathwish to be a goblin or kobold wandering the streets of lower, would the merchants actually deal with them anyway? (I don't want to metagame NPC's).

Also, are there any NPC's outside of Sanctuary that would refuse to deal with kobolds or goblins?

Now that they have guards, they'll do business with you, but I wouldn't say they like you. I can't think of any NPCs outside of Upper Sanctuary who would refuse to deal with you, if we change our mind we can make it so they'll automatically go hostile though. I appreciate that you thought to check, though.