I think referring to Moses turning the waters of Egypt to blood is false. God turned the water to blood. Moses was following Gods instruction in each plague. Moses was the one who relayed the message through to Pharaoh from God in all cases. Moses did not tell or ask God to perform the plagues.
This is like saying a news reporter caused the CV lockdown because he/she brought the news out of the briefing room from the President or Prime Minister to us.
Elijah was no different, he followed the instructions of God in the same way, telling Israel and its king what God had told him to say. In fact, the opposite occurred. Elijah was the one who’s prayer for rain was recorded in detail, despite the word of God saying it would rain. Like the prayer of Daniel, who in similar circumstances was experiencing the punishment meted out in his people for their sins, and at the end of the 70 years was praying that God would relent, the recorded prayers of Elijah was for rain. Both knew that Israel continued to sin against God, and both prayed on their behalf for relief.
Men of God are those who intervene between God and man on behalf of humanity.
Did Elijah pray for drought? Yes, under instruction from God. Did Moses stretch out his rod over the water? Yes, under instruction from God.
The two witnesses you refer to are different. These are the two Testaments, the Old Testament and the New Testament. They are not people.
There are parts of your question where I can see you faithfully follow the Protestant Historicist Interpretation uncovered by the early reformers, but other parts follow Futurism. Note that Preterism and Futurism were revived in the Counter Reformation to counteract the Historicist school of the reformers which pointed to the Roman church as the persecuting beast of Revelation and Daniel.
Futurism also relates to Premillennialism and Dispensationalism, which from parts of your question I read that you prescribe to. Examine the prophecies carefully and try to follow the reformers steps in deciphering the prophecies.
Support
The OP tells me I am splitting hairs in ascribing the plagues to God not to men. Here from Exodus 3:18-20 where God speaks to Moses from the burning busy and says as follows:
“The elders of Israel will listen to you. Then you and the elders are
to go to the king of Egypt and say to him, ‘The Lord, the God of the
Hebrews, has met with us. Let us take a three-day journey into the
wilderness to offer sacrifices to the Lord our God.’ But I know that
the king of Egypt will not let you go unless a mighty hand compels
him. So I will stretch out my hand and strike the Egyptians with all
the wonders that I will perform among them. After that, he will let
you go."
From chapter 7:4 God again is recorded as instructing Moses as follows:
"Then the Lord said to Moses, “Pharaoh’s heart is unyielding; he
refuses to let the people go. Go to Pharaoh in the morning as he goes
out to the river. Confront him on the bank of the Nile, and take in
your hand the staff that was changed into a snake. Then say to him,
‘The Lord, the God of the Hebrews, has sent me to say to you: Let my
people go, so that they may worship me in the wilderness. But until
now you have not listened. This is what the Lord says: By this you
will know that I am the Lord: With the staff that is in my hand I will
strike the water of the Nile, and it will be changed into blood."
So the question here is, is the OP correct in saying "These men actively caused the events to occur."
I read it as saying these men followed the instructions of God, but it was clearly God actively causing the events to occur. I do not believe that God requires the compliance of men in order to perform any deed. Nor do I believe that any man can perform these deeds without the instruction of God.
The men were there to give the meaning of the events, to record the hand of God in action. God worked through them, as when Moses struck the water of the Nile, to show to all present, and to all future, that it was indeed Him that sent the men.