Chuckles and Kathy had been dead in that time frame for the past 17 years according to Naomi. Putting time on track would mean making sure that Kathy and chuckles died, and nudging it off track to keep them too kicking would have assassinated Icheb and Naomi in their futuristic present.
Or was no one being selfless because they were all returning to parallel timelines happy as larry? ...Although then why did Seska try to Hijack the day saving to put her time frame to the fore front if she would have arrived out the other end intact when it seems remarkable that the Borg would sacrifice themselves to help Chakotay considering how belligerent and "traitorous" Seven was to the Voyager Crew and the rest of the universe for the first couple episodes after Kathy kidnapped her?