There is no mention of brown dwarves in Tokien. He does mention 'Burned Dwarves'. At the Battle of Azanulbizar there were too many dead to bury so they heaped them all and burned them. A 'Burned Dwarf' was greatly honored in Dwarf-lore.
Those stars are called brown dwarves.
They radiate aways whatever little energy they have to become black dwarfs.
Several times smaller than our Sun. Details vary, depending on the type of dwarf star (a red dwarf and a white dwarf are quite different things), and the exact mass.
If you mean "stars", the smallest real stars are called red dwarves. Brown dwarves may be smaller still, but since they don't fuse hydrogen-1 into helium-4, it's doubtful whether you should classify them as real stars.
The coldest stars are the red dwarves. Anything colder than that would be a "brown dwarf", which is no longer really a star.
The Three Dwarves are sitting
No, female dwarves do not have beards.
The dwarves steal Mithril. A very important item that is known to be famous according to the dwarves.
You can check the Wikipedia article "List of nearest stars". Note that it is quite possible that not all stars up to that distance have been discovered, since red dwarves and brown dwarves are quite difficult to detect.
The dwarves and the elves dont get along.
The Dwarves - book - was created in 2003.
Dwarves Deep was created in 1990.