Can entries to the federal and state be changed without 'amending'? We have not e-filed or mailed, though we had gone through the final review as we thought we were done

Yes, if you have not yet e-filed or mailed the return, you can go back in and make changes before filing. 

You can get back into your return using the steps here below:

• Log into your TurboTax account and click My TurboTax at the top
• You should be on the Tax Timeline now
• Scroll down to SOME THINGS YOU CAN DO section
• Click Add a state (not really adding one, just a way to get back into return) 
• And make the changes you need to