New to QACAs

One of the accounts has inquired about a QACA SHNE 401(K) for a huge home health care agency, composed of office staff, home health care workers, and nurses.

From what I'm reading from ERISA Outline Book, but possibly incorrectly, each group can either be in  one plan or 3 separate plans - as long as each class has a uniform percentage, with a minimum of 3%.  All requirements for safe harbor status will be met. Each plan would need to pass 410(b)?

I do not believe the plan could be effective mid-year as the 30 day notice was not met, but to be effective for 2022, as long as the plan is set-up, doc prepared and signed by 9/30.

No profit sharing.