A group of us in SC bought a dump trailer load from this place in VA.several years ago. Its was good coal. I don't know what it would cost to get it to you. Monger Coal & Oil Inc 600 Mount Hermon Rd
Elkton, VA 22827
540-298-1256
Build a side draft like this and you will have no problem with the smoke. Only problem is you will need to go straight up through the roof. I built mine like this and it works great. http://www.beautifuliron.com/steelhoods.htm
There is a thread on here about the Hofi style side draft that might work better for you.
Charcoal comes from wood. Coke comes from coal. Charcoal as we are referring to it is wood that has been burned until it forms coals and then it's extinguished. I've never used it but i do plan try it sometime.
In my opinion go watch someone demonstrate forge welding that explains it well as he is doing it. That is when it started to make sense to me. I don't look for the sparks. I try to watch the surface of the metal. You can see when the surface of the metal begins to get molten. That is when I know i have reached welding heat. The metal will be white hot and the surface looks like it is greasy or runny. Sometimes I see some sparks and sometimes very little sparks at all. Coke or coal doesn't matter but forge welding with a fairly new fire that hasn't had time to make a lot of clinker helps. If you have been forging for a few hours you might need to stop and clean the clinker out and then get ready to forge weld. I'm still not that good at it either but hope practice will help with that.
I was wondering if you are using quick connectors for the air hose. Most of the common connectors are 1/4 inch. If you went to a 1/2 hose with a 1/2 quick connector you would see a huge difference.