Is it also true that I cannot extract this information unencrypted into Excel once I have used the private key to view it?

Is it also true that I cannot extract this information unencrypted into Excel once I have used the private key to view it?  How can I pull a roster/report of the information collected that is not encrypted?

That is correct, once the information is encrypted, you cannot decrypt it if you download it, you can only view it in the submission page.

If you have reverted the encryption in the form, you should be able to download a report with new submissions and see them. You can simply make partial downloads.