Just relax, and keep checking out this forum. There is just TONS of info on here to make your planning easier. I know I felt the same way but finding this has been a Godsend and my planning is going so much better. Good Luck!
So sorry to hear that. It is so frustrating when people say "yah yah yah I'm coming" and then change their tune. It's especially disappointing when it's family. Just have fun with your friends and the others will be sad when they hear everything they missed out on.