Does the short plan year affect anything that's trying to be accomplished - does the plan define the limitation year as the plan year, or as the calendar year, for instance?
Don’t forget that the plan will have to issue Forms 1099 so values will have to be assigned. If it is a direct rollover, the distribution has no tax effect, so the accuracy should not be important to anyone, still … .
Does the document specify? Make sure it even allows. I assume the NHCE was offered in-kind distribution and elected cash and they have documentation for such, otherwise you have BRF discrimination issue.
Assuming plan document allows but doesn't specify precise method and NHCE offered and declined, then I think they can divvy up assets how they want, equaling their correct individual distribution amounts.
Not sure what you think is odd about it? Fairly standard operating procedure for many plans.
Curious why you say, "there's no need to suspend benefits since in service distribution is allowed"? Unless you are giving actuarial increases to the active participants for delay retirement, you would still be required to provide a suspension notice to anyone working beyond NRD.
Somewhere buried in the regs it says you can calc it on a cash basis (in many more words than that). I don't recall anything about having to be consistent so I'd say you could change.