Would be a rather theoretical, but not impossible idea, but since you've asked . . . here goes 

Sometimes a court may exert pressure on the parties to mediate.  This could occur by a court pointing out that OP was & is obligated at the outset to make a determination of Farr's eligibility, also pointing out that OP's action[s] regarding disqualification were not timely and came too late.  Thus were legally questionable & open to being litigated at the trial.  That kind of thing would be an incentive for OP to back off, and admit its error in printing those ballots in question, containing Farr's name. 

Arguments could say:   They were 8,000 examples of ballots out in the world --all declaring Farr's eligibility.  Ballots being looked at and in the voters hands for weeks . . . 

Finally, OP conceding to one-time eligibility exception for Farr in view of OP's own untimeliness -- but not to be considered a precedent for the future.  However, I'm not predicting this would occur.  Seems odds may not be favorable.  Especially at this time.  YES its getting late on the calendars.  The factor of lateness again.

Some few judges may have tendencies to prefer mediations.  Others may not. Reading tea leaves Then there's always the idea of the "hazards of litigation".  The unexpected.  Multiple plaintiffs.  Any more rabbits from hats.