- [ ] have a well-seeded database so that I am able to simulate a number of different scenarios for the user stories below.

[stephdurino]

By doing this, you really set yourselves up to tackle many of the points throughout the tiers. In the long run, this will save you, potentially, tons of time.
For example, seed hundreds of products with dummy data so that when you get to the “pagination” user story, you won’t have to worry about adding more products.
Likewise, add a bunch of users with products in their carts so editing the cart can be worked on without already having the “add to cart” functionality built out.