Supplemental information for spouse beneficiary (I-130A)

I'm planning to file the I-130 as the first step toward a CR-1 for my foreign spouse and am wondering what to include in her employment history as she has one past employer who's no longer in business and no current contact information for them. She also worked as a realtor in the past but is unable to find her license so would be unable to verify her employment if asked. Just wondering if the USCIS typically verifies employment references or asks for verification in the form of paycheck stubs or tax filings and whether it's advisable to leave these references out?