I thought the I-601 was the form related to hardship, and that the I-212 was the waiver of inadmissibility.
Correct.

When you said your wife had overstayed a year, it sounded like the marriage was quite recent, so I didn't address the I-601. My apologies.

Can you document severe hardship to you if she were to be deported?

If she leaves voluntarily, would it just be the I-601?
No. She would need to file both if you're planning to claim hardship.