Coal can't be turned back into coal ore once it is mined. Since there is no enchanting in Minecraft PE, there is no way to obtain coal blocks in survival.
You don't.
There are no flares in Minecraft. If you mean torches, you put a stick and a piece of coal in a crafting grid. The coal goes on top of the stick.
dig underground
Coal is very common. Caves are a good source of coal, but if you are mining, coal is most common at y=48.
A single piece of coal can perform 8 furnace operations in minecraft 1.6, so that means 8 pieces of cobblestone.
you cant
you cant.
you cant
you cant
you cant
You cant