401(a)(26) issue

We have a defined benefit plan, covering only a Key employee, and then  in 2016, 3 other employees joined the plan and accrued at least a 0.5% accrual. The plan was frozen 12/31/2016.  No other employees.  The question I am dealing with whether I am satisfying 401(a)(26) for this frozen plan since 2016 as there are no accruals as the plan is a hard freeze. Since there are 6 "participants",  am I satisfying 401(a)(26) since 2016? I find the reg hard to follow for db plan subject to a hard freeze.

Opps. only 4 participants.