wooow! back under the living again... food poisoning is one hell of a thing...
talking about poisoning, there is a plethora of poisons you could concoct. It'll all depend on what you want to make and how much of it you want. You might need to find shady dealers for certain ingredients or need to hunt down beasts for them.
I'm all for creative thinking with crafting
Tiefling society works pretty much as it normaly would. they are scattered across the world and generally distrusted because of their demon blood. however they have made a country for themselves.
taking claim of a valley between the mountains. (though not on this continent) every Tiefling knows where it is, yet not every Tiefling wants to live their lives there. as it is a very Lawful society.