Also check with Apple Store if you have one nearby. Last year when the 7Plus came out I would check everyday and happened to grab one is stock. The key is check a few times every day. Good luck.
There is always a possibility but I could certainly camp out if you do plan to get one. Unless this launch is a complete and utter failure on Apple's part, I would assume that this phone with be a hot commodity. Best of luck to you!
Apple confirmed their stores would have a few on hand 11/3, but to get there early -
No idea if any carrier stores will also have stock. I did see Best Buy with pick-up options on 11/3 (last night at 2:15 cst), but I dont know if they hold any back for walk-ins. good luck!