Toilet paper. By far the biggest market out of those listed above, bulky and inconvenient to pick up at the shops while doing other things or to stock up on, catastrophic not to have. You'd need two/three levels of comfort, probably.
You don't just order toilet paper from Amazon, subscription or not? (Although I'd imagine toilet paper usage rate is pretty consistent, so that would be easy to set up a subscription for)
No. Amazon subscriptions have been really frustrating for me - not enough flexibility around amount and timing, so either I subscribe to just less than I need and run out anyway, or just more than I need and have it piling up.
The one other thing that could be a good restock is rice. A solid restock on quality rice is something that could be really valuable for folks who cook Asian food regularly, and it's something that people generally make on a pretty regular basis, but may not have a good local store that has quality options for.
Rice is dirt cheap and low margin. The sort of people who eat rice everyday are also the sort of people who buy a 40lbs bag that lasts for months because rice doesn't go bad. Also, my (stereotypical) impression of people who cook rice everyday is that they are not rich and willing to spend money of this type of luxury.
My guess is that rice is one of the last products that automatic restocking makes economic sense for.
If you want to get VC funding, pick the one with the biggest market.
If you want to build a profitable business sooner rather than later. Figure out which 3 would give you the best marginal profit and choose the one you think you can execute best on.
Your list are all products we're planning to address eventually. The real question is: what do we do next?