My wife's Employer's State ID # (Box 15) states "0": Can I use the Employer Identification Number (EIN) from box 12b in lieu of the Employers State ID Number (Box 15)?

It is okay to enter the employers federal ID number in place of the state ID number. The Employer’s federal ID number is located in box b of your W-2 form.  Your State Department of Revenue will be able to easily identify your employer from their 9-digit federal EIN