I have to run bitcoind in one command prompt (to get bitcoin-cli to work).
Yes, you must have Bitcoin Core (bitcoind or bitcoin-qt) running in order for bitcoin-cli to work. It is a tool that interacts with Bitcoin Core through the command line.
When I open/check Bitcoin Core, there are no additional addresses added.
Where are checking to see if there are addresses?
I know I could add them individually using Core's console, but I need a batch file since I have many addresses to add and wouldn't be able to do them one-by-one.
You could use the importmulti command instead. That allows you to import multiple things (private keys, addresses, etc.) in one command.