A war cry is something that you do before you take action. A whoop of triumph occurs after you have succeeded in something. A war hoop is used to call people together. You use this expression to describe someone in the process of “war.”It could be any type of war. For example: The child gave a war hoop as he jumped on top of his brother. A battle cry is used to describe the uniting of people under one idea. A victory cry is something that you do when you have succeeded in something. So, I would not recommend using these interchangeably because they have slightly different connotation. I hope that this answers your question.