Hmm, commoners/non-hero type adventurers.
I don't like the wording of the farmer's rule, reminds me of the US fire of wraith and ball of flame, where first it says something happens full stop. Then it says oh, unless this happens. I think it would be better if it said 'Any time you drink a potion or eat food, that item is not removed from your inventory and may be used again if you avoid rolling a skull one one combat dice.
I'm not sure about the blacksmith either to be honest. It would be easy if you added an equipment breaking mechanic but I'll doubt you'll want to. Maybe a discount on equipment as he can but shoddy stuff and repair it, but then why wouldn't he do that for the others? Then again the dwarf has a skill that benefits everyone, but at least it's him that has to do in game. You could put stuff in the quests that only the blacksmith can fashion into something.
Another couple of ideas for you to make a full commoner set. Dwarf miner and elf witch-doctor. The dwarf miner is from warhammer. The witch-doctor could make his own potions. Here's my miner if you didn't spot it in my hero thread, help yourself.

I think the standard version is quite nice for a miner, he would definitely know how to swing an axe. You might want to make him defend with two dice and have standard movement if you are interested in using him, though that might overpower him with five attack dice using a battleaxe. Maybe the target gets one less defence dice if he's using an axe or you could start him with a hand axe and let him always attack with an extra dice when using an axe.
Miner: M6/Lowest two of three dice A3 D3 BP7 MP3Race: Dwarven (Dwarf).
Class: Miner.
Equipment: Double Axe, Banded Mail, Helm.
Special Rules: +1A with any type of axe if you don't move. Automatically spots and disarms falling rock traps in the same room or corridor. Additional +1D against falling objects.
Veteran: +1A using any type of axe if you move no more than half rate.
Master: Optional dispel attempt against any hostile spell affecting you by rolling a combat dice, on a skull it's unaffected, a white shield counters it and a black shield rebounds it back against the caster + optional dispel attempt against an enemy spell cast in the same room or corridor, a skull it's unaffected, a white shield dispels it and a black shield dispels it and the spell is lost.
Legend: Defends with black as well as white shields.