I'm going to offer what I would do, were I in your shoes. I'm sure others will chime in with their experiences/ideas, because we've got people from all walks.
I'm not sure I would do a 6-3-6; it seems very restrictive. I get where you're coming from- you want belt AND suspenders. But I think having a "if all else fails, we've got this shoe leather we can make soup out of" idea is going to serve you and your family well. If you are blessed with a large pantry and a freezer, you've got an excellent start. What I would do is make a log of everything you've eaten in the last few weeks- that's your normal consumption. If your wife is the de-facto chef, have her make a list of foods that she likes making, and then a list of meals that she likes to make for special occasions. Keep in mind that although it's hot as hell out now, it will be winter soon- that means soups, stews, hearty breakfasts and warm beverages, too. Holiday meals. Your pantry should reflect that- dry storage such as canned veggies, dried beans, spices, stock and broths, rice/grains, cereals, baking supplies, yeast (for the love of little green apples, get yeast!) and such. Soup and stew-making stuffs can mostly go here.
What we're doing is keeping meats in the chest freezer, and the fussy stuff in the freezer below our refrigerator- veggies, frozen pizza, ice cream, and bits and bobs. But our freezer is mostly for meats and flour, because I can our veggies and fruits. I take things like sugar (or sugar substitutes, as we are a low-carb family due to medical issues) and put them in airtight containers that I can see into at a glance. Nothing drives me up a wall faster than thinking I've got some sort of foodstuff in storage and finding out that we're out of it or it's gone bad. Beverage mixes are important- keep those handy.
It's easy to get overwhelmed, too- try and keep an inventory on a clipboard.
Don't forget fun stuff like Jello (or whatever treats you prefer.) If we have a strict lockdown, I don't think there will be an easy or 'fun' trip to the store for a while. So buy popcorn while you can.
Think about what was not available before. Eggs. Milk. Butter. Pasta. Rice. Bread. Bread, you can make with a bread machine as long as you have basic ingredients. Eggs can be frozen (though not in the shell.) Milk? Absolutely can be frozen. Creamer? Not so much. Better get the dried stuff and stick it in the just-in-case section.
Getting the basics, rather than the already-completed meals (soup fixings, rather than the ready-made cans) may be better for long-run storage. You can make a lot of different foods with combinations of basic ingredients than if you had 40 cans of the same soup. Food fatigue is a REAL thing.
Before I forget- this will show you that the expiration dates on these foods are arbitrary for most things. Sour cream and yogurt can last far longer than the date stamped on the package.
One other thing, before I forget- do you have a Food Saver? Get one, and get extra bags. You will not regret the investment.
That's all I can think of for now.