Do they both shut heaven & turn water to blood?
Revelation 11:6 These have power to shut heaven, that it rain not in the days of their prophecy: and have power over waters to turn them to blood, and to smite the earth with all plagues, as often as they will.
It doesn't say that only one has power to shut heaven, and that only the other has power to turn water to blood.
That would go along with the popular teaching that one witness is Elijah and the other Moses.
However, doesn't it read like they both have power to do both?
Why must it be people that lived before?
Why can it not be two men alive during the time of the tribulation? No one teaches that the 144,000 are people from the past, so why must the two witnesses be people from the past?