what should the adopting employer get each year?

We're reviewing our procedures for a closed MEP (for a PEO), and we're looking to see what the adopting employers are REQUIRED to get versus what it would be USEFUL for them to get.  Not in terms of legal notices, but all the admin work.

Examples:
Top heavy test results - send.
Full 401a4 detail... not sent to the individual adopters.  No real good reason.

So, yeah, like that.  Is it just more sensible to treat this is X number of standalone plans and send them all the testing, etc. applicable to their population/'silo' portion of the plan?  What are others doing?

Thanks.