Best left to a gunsmith
There is no such weapon.
Revolver or semi-auto?
38 special is only a revolver caliber. that's like saying a 44 magnum revolver or a 500 special revolver. a revolver is a revolver
There can be more or less than 12 depending on the specific revolver and just how far down you disassemble it.
It depends on what you mean. A .38 revolver may be a .38 special, but there are other types of .38 besides just the special round.
Yes, you can shoot .38 caliber ammunition in a .357 revolver because the .357 revolver is designed to also shoot .38 caliber ammunition.
No
A ".38 +P revolver" is simply a .38 Special revolver which is rated to fire +P loads. It's still a .38 Special, and the +P doesn't change the dimensions of the round itself.
Have to know if it's a revolver or semi-automatic in order to answer.
Best left to a gunsmith
Yes, you can shoot .38 Special ammunition in a .357 revolver.