It's not a big dataset, but you can use
Telecommunications Towers and Antennas
Connecticut General Statutes §16-50dd requires the Connecticut Siting Council to develop, maintain and update on a quarterly basis a Statewide Telecommunications Coverage Database that includes the location, type and height of all telecommunications towers and antennas in the ...
Open Street Map (OSM) has a tag name=Walmart.
In December 2017 Brandify provided Open Street Map with a database of all Walmart locations, and details This import took place January 2nd, 2018 and used OSM Conflator.
So it's unlikely to have when the store was opened.