I think the plan was probably deferral and match only and there were a number of eligible employees who did not elect to make 401(k) contributions and did not have any balance in the plan. At least that's how I read the OPs post but maybe I'm wrong.
I'm trying to understand the scenario.... didn't have an account...meaning the employee was eligible and didn't have a plan account open? Or the employee wasn't eligible and didn't have an "account"?
Sorry for the confusion....
I might suggest it being deemed a QNEC to avoid putting any sort of vesting schedule on it. But yeah, your conforming amendment is going to need data on who actually got the CODA option versus who was just given the 1,000 unilaterally as a plan contribution versus those who got it unilaterally as a bonus.
I'm not familiar with Virta, but it certainly sounds like a medical expense. If so, the employer's coverage of the expense creates a group health plan subject to COBRA. Excepted benefits avoid the HIPAA portability provisions and ACA market reforms--but they don't avoid COBRA.
From the ever popular Google search:
"Can you undo a Roth conversion in 2021?
You can't reverse your decision
Today, recharacterization of converted Roth funds is prohibited by the Tax Cuts and Jobs Act. In other words, there's no going back once the conversion is done."