Please provide inputs on the following questions.
What the documentation means re: access to the analytics API is that if you attempt to make a ShopifyQL query or API request against the reports API on a shop that is not qualified (is not on the Advanced Shopify plan or higher), then the request will fail. They can still use your app, just the part of it that interacts with the analytics API will not work.
You can make queries with ShopifyQL using time stamps as shown here.
|26 seconds ago|
|an hour ago|
|2 hours ago|