Yes. OSHA lists electrocution as one of the most common causes of fatal workplace accidents.
All do - some just have greater conductivity than others
Static electicity.
water
yes all materials conduct electicity , but some are good conductor , some poor and some very poor
electicity
kilowatts
yes
yes
yes, you can you need some metal in the saltwater though or it wont work
Yes.
yes
Thomas Edison