to use the dwarf multicannon, complete quest dwarf cannon. to use the hand cannon, complete the giant dwarf. those two quests befriend dwarfs.
You can find them in the mine in Varrock
It depends on the pantheon.
You kill chaos Dwarves there I think, and they drop the key.
you can go to grand extange or to the place where you bought it orginally(the place with the dwarves)point is, you have to buy it back
The same way you befriend anybody.
There already is, both a dragon warhammer, and an off-hand dragon warhammer. It requires Attack level 60, and you need to complete the quest "Birthright of the Dwarves", to use it.
The Three Dwarves are sitting
The dwarves steal Mithril. A very important item that is known to be famous according to the dwarves.
You befriend Captain Hook by helping him defeat Peter pan.
The Dwarves of Rockhome was created in 1988.
Dwarves Deep was created in 1990.
The Dwarves - book - was created in 2003.