Passover Mystery

Another set of questions that I hope will result in answers.1) The story of the Passover in Exodus has it that Moses at first declined to talk to Pharaoh as he felt that he would not be listened to. He was right.. Why didn't God talk to Pharaoh directly rather than have Moses do it with no results until innocent people were killed; people that had no power to free the Jews. This rises serious questions about God's intelligence. Any answers?2) In the story of the Passover it is the "first born" that are slain. Some have developed information that the first nine plaques were of natural origin and may account for Pharaoh's lack of action. None have explained the final plaque the death of the first born. A
natural solution would have it that it was a disease, such as dysentary or something similar to cholera that struck down the "first born of the year" or "newly born". Infants quickly dehydrate and perish when infected. A disease passed to its human hosts by infected food. The Jews did not suffer as they in effect quarrantined themselves in their homes and ate food that the general population would not normally touch.3) If God didn't do it, and disease germs do not discriminate between first born and others: then the one remaining answer was it was caused by humans who knew who was the first born in Egyptian families; the Hebrew servants. Any answers to this one?