If a solo S-corp has accumulated earnings from past years, but no earnings in the current year, are they required to pay wages in the current year? How would distributions work?

See https://www.irs.gov/pub/irs-news/fs-08-25.pdf

The amount of the compensation will never exceed the amount received by the shareholder either directly or indirectly. However, if cash or property or the right to receive cash and property did go the shareholder, a salary amount must be determined and the level of salary must be reasonable and appropriate.