I think this is just a doubly weird year. The dub changing the airing to these batches, and the hiatus due to coronavirus. Both are unrelated things, but because they both happened the same year, it's confusing. I agree that if the December 2020 Japanese episodes are episode numbers less than 48 (the average episodes a year since AG) because of the hiatus, then they would have to be in batch 4.
If we do the math a bit right.
3rd batch comes out to be episode 36.
4th batch would come out to 48 if they are doing 12 episodes. That actually would come out to be November 29th which seems to work which mean the potential 2-4 episodes of December would be in the 5th batch.
But the first season of Sun and Moon episode ended on episode 43 which then makes it difficult if they would include the few or all of the December episodes.
Again I don't know the context of the dubbing, there maybe a reason for why the episodes had like a 48 episode seasons. Which would work out. But I also think it depends on how the dub gets these episodes. Do they only get the November episodes in the context of dubbing them, and then when they are done and have that be finalized or too far into production is when they get the December episodes?
If December only has 2 episodes (accounting for two weeks of breaks), they have episode 25 into the 2nd batch (so that's 13 episodes) that would mean then the 4th batch would only have 11 episodes, if you give batch three another 13 episodes that means batch 4 only has 10 episodes which would be able to include the December episodes.
Either the hiatus allowed the Dub to magically work out 48 episodes a season this generation with episode 48 being the last November episode but of course in reality we should've been already at episode 39 by this week's time, which means that we would've had about 55 episodes for both the year of 2019/2020.
Episode 43 would've aired September 6th if there were no breaks at all. Which means episode 48 would've aired October 11th potentially, so that means that would've been the 4th batch which means that it only would've gone to October epsiode., but then the 5th batch would've had to include the rest of the season including some of the next year's episodes for a 12.
So I guess I'll have to concede here. 48 ends now in the November, so they don't have to include December episodes in that batch. Whereas originally it wouldn't have mattered because 48 would've ended in October, and thus the rest of year would've easily been included in the 5th batch which would've likely been a new season.
But I do have to wonder since 48 is timing up WITH November 29th (if there's no breaks of course), and there's only two December epsiodes wouldn't they just include it, since episode 50 would've been likely the last October.
I just don't know how they're doing the dubbing or how they are getting the episodes. I don't know if they are getting them quarterly as it were where because of the Hiatus they would get the December episodes (49-52) or do they GET straight up 48 episodes (well not all at once obviously, but the last episode they get to dub the next batch ends in episode 48) so they can ignore the December episodes, until they get to doing the next season thus maybe it sits an email or something.
It would really HELP to know exactly how they are given the episodes. If its like the past they definitely get the episodes before the actual episode airs in Japan (so I assume when the episode is fully finished and completed), but is it weekly based or do the Japanese wait for a few episodes to be finished and then give them to the dub production team.
Ultimately whatever happens will happen, either the 4th batch will only include episode 48 the last November episodes if they are strictly sticking to a 12 episode release. Or they might decide to alter it a bit due to the actual content of the episodes, but I won't get into that because of spoilers. I just assume the dub would've already be in possession of episode 25 because it most definitely was likely to air before the hiatus stopped the episodes at 22, since the series resumed with 23 on June after a month and half break.
