Line 4 on the 5500 is used to report a change in the name and/or EIN of the plan sponsor.
Note that it is the plan sponsor's EIN that should be used on the 5500. Maybe there is something I don't know about the multiemployer plan world but usually the plan sponsor is not the trust. See the instructions for line 2 for the definition of plan sponsor.
The EIN for the trust is probably reported on Schedule R of the 5500 as the payor that paid benefits.
This whole thread reads like the RMD is being paid from a DC plan, not a cash balance plan. Sounds to me like the participant gets the normal form distribution as required by 1.401a9-6. Hope the election forms indicated same. Anything else is just creating a bigger problem for the future when somebody comes in that knows what they are doing.