Ready to mail. Forms printed. Not mailed. Discovered additional wage information is missing. Amended with 1040X. Do I need to attach the original non-mailed 1040?

If you printed the original return, but never mailed it, you shouldn't prepare an amended return.  The IRS wouldn't have received an unmailed return, so instead you can simply correct the figures and mail an original 1040 to the IRS.

Cancel the amendment.  Then click Add a State and it will put you back into your return and let you eFile or mail.