Shinji had an additional line in the trailer, so the additional fight leads me to believe Shinji may actually do something for once in this arc with either Bazz-B or maybe actually fighting Bambi for a bit.
Regardless, the better discussion is where this cour could potentially end since going by the first cour the second would end right around Chapter 606 which is literally in the middle of Ichibei vs Yhwach. Not really a good spot to end.
Thus, could they actually accelerate the adaption so the 2nd cour ends when Yhwach reveals the Almighty and beats Ichibei? No, they're adding extra stuff as we know so it doesn't seem they could accelerate it.
Thus, I think a proper ending would be around Yhwach's invasion of the SK Palace, which is the end of 587 or the start of 588. However, this is only a 45ish chapter adaption for the 2nd cour as opposed to the 62-3ish adaption of the first cour. It doesn't seem there is a good middle point between 606 and 587 to end, but given we know they're actually adding an additional prolonged fight and possibly other smaller fights (Kubo did mention the Bambies getting more screen time), I'm thinking this cour would end around 588.
Happy New Years as well, hope everyone had a good holiday.