When I go to "items" and see my inventory list, it doesn't match what I find when I go to Store Editor (on the actual store website), when I click "edit" on a particular item I'm selling - that screen shows a different inventory count!
I am not sure which screen is correct or why they are different?
I think I know what's happening here. When you're adding items to your Square Online Store you have the option to create a new item on the fly, or import an existing item from your Item Library.
It sounds like you created items on your Online Store rather than importing them from your Item Library.
If you import the items they'll have a shared inventory, so in-person and online sales pull from the same place. 🙂