I could not have said it better myself. If there is one thing that can unite Christians and Muslims it would be acknowledging that all (independent of belief) were created by G-d. If they focus on that both peoples will be able to accomplish so much together. The reality is we will all disagree on something; you highlighted how even within each religion there are different denominations and beliefs, and yet they are all united. Therefore the first step to working together is acknowledging this similarity.