Just a few small things about the Stout Mines... Who is the "charred body"? Is he important? How many pieces of Dragon Ore are there? I have found one... do I need another one or can I just steal it back from the King and use it again? Thanx.

No significance to the body other than a warning that there are fire-breathing critters around. Luck of the draw with finding dragon ore, but I usually find 2 or 3 chunks. You technically only need one set of dragon armor, but each set sells well (approx. $10,000), so it's worth the wait for Freyedies to make some extra sets.

Do I actually need to find other shards, or can I give one to the King and steal it before it disapears and get more than one set of armour with only one shard of Dragon Ore?

The dragon ore is all in one place -- if you only got one chunk, that's all you're going to get. I don't know if you can steal the ore from him as he is working it, but you can certainly try, as you may want to get the treasury key off of him. You should keep saving the game though, because he's cleverer than the guards and may catch you at it.