Right from the beginning, there was no doubt in Moses' mind who would be going.
Exodus 7:1 Then the Lord said to Moses, “See, I have made you like God to Pharaoh, and your brother Aaron will be your prophet. 2You are to say everything I command you, and your brother Aaron is to tell Pharaoh to let the Israelites go out of his country.
All the Israelites, men, women, and children.
Pharaoh understood that as well.
Pharaoh summoned Moses and Aaron and said, "Pray to the LORD to take the frogs away from me and my people, and I will let your people go to offer sacrifices to the LORD."
The word "people" here unambiguously refers to all the people of Egypt and all the people of Israel. There was no misunderstanding or miscommunication here.
Then why did Pharoah say the following in
No! Have only the men go and worship the Lord, since that’s what you have been asking for.
It was a bargaining tactic. He thought he could bargain his way with God. It didn't work.
Then the plague of darkness came and Pharoah retracted.
Then Pharaoh summoned Moses and said, "Go, worship the LORD. Even your women and children may go with you; only leave your flocks and herds behind."
More bargaining but it didn't work.
Did Moses only request the men to go to worship the Lord?
Was there a misunderstanding between Moses and Pharaoh?
No. It's just that Pharaoh thought he could bargain with Moses/God.