Hello! This is my first thru-hike too so you're not alone. I have done a lot of long distance hiking, though, so I have a little advice as far as food storage.
Your best bet would be to get an Ursack and use odor-proof plastic bags. That way you can camp anywhere and not have to worry about finding a suitable tree to hang a bear bag. Bear canisters are heavy and bulky but unless you're going ultra-light they're an option. I rented one in the Adirondacks because it was required and rangers check everybody. I found it to be a nuisance but a neighboring camp about a quarter mile away had a bear problem so I guess it saved me.
And sleeping with your food, while I have done it, is incredibly dumb. In southern AZ especially the risk is minimal; few bears, and mountain lions don't want your food. But if a bear DOES smell your food and investigate you'll end up with a ripped tent, ripped sleeping bag if he drags you out, and no food, which would cost way more than the 90 odd dollars an Ursack costs and possibly end your trip or put you in the hospital.
So yeah Ursack. Second choice is hanging a bag. Third is a bear canister.
As far as snakes, I wish ALL snakes were rattlesnakes. They are polite snakes in that they have many lines of defense. First is hiding, second is running away, third is rattling, and fourth is biting, and even when they bite it's a dry bite 50% of the time. Basically stay on the path and if you see a snake, don't pick it up, don't step on it, give it a wide berth, and be careful when the trail is overgrown.
Hope that helps. I'd love to hear more about your planning!