No English King was executed after the English Civil War. The execution of King Charles I occurred during the Civil War.

No - the English had nothing to do with the American Civil War.

Third English Civil War happened in 1649.

Wars are usually named after the winner of that war. Due to the fact that the war is called the English Civil War the English won the war.

War of the Roses was the civil war, it can be confused with the Hundred Years War, but the Hundred Years war had to do with England and France which is not civil to the English.