"Retained earnings gets closed to each shareholder's equity? Wouldn't retained earnings be reported on Schedule L of an 1120S?"

Do you have a CPA inhouse? As was mentioned in your topic here: https://accountants-community.intuit.com/questions/1896747-onboarding-clients-to-qboa-cash-or-accrua...

You are again asking a combination of "how to for QB" and "how to for taxes." This forum is a great place to learn how to use the Tax Preparation programs to prepare taxes for clients, for a Professional tax preparer that has to keep current with tax rules and regulations. It isn't a great place to learn tax accountant fundamentals.