That'll take a while. Plus they are already airing them at 5am eastern. I don't think fans need to see the episodes they've seen like 6 full cycles. The new episodes on their own will be just fine. Or they can bump up the last 10 episodes from the original series and air them at 12am till they can air the Final Act ones.
Also saw the final episode of the sub. Man what a wonderful ending [just as in the manga], it's so sad it's all over now. But at least finally Naraku is finally gone. Now time for the studio to make a 5th movie