The main question: considering that Tsurugi is under the disease right now and there's 3 hours until the harvest, what happened within the three hours that resulted in him being completely fine (as we saw in chapter 83, when there were only 13 minutes until the harvest) and Norisuke presumably dead or close to dead?
Presumably, the next chapters will have to show:
1. Josuke's encounter with the head doctor at the TG University hospital.
2. The convergence at the Higashikata estate. Whatever happens, it is likely to be JoJolion's endgame or at least, pre-endgame, much like the D4C fight coming before the High Voltage arc. And it will take place in the Higashikata estate, as that's where the branch is, and also where most of the interest is at.
So the key players likely to be in this endgame(?)
1. Yasuho. As we saw this chapter.
2. Josuke. So at this point, from Josuke's side, he has around 24 hours or less until the harvest. (Since it was around 12PM 48 hours before the harvest when Josuke and Mamezuku learned about Satoru's lecture, and then Josuke woke up 10:52 AM the next day, and had the encounter with Holly, leaving him roughly a day) He probably will have another encounter with Satoru, as that is his goal currently. But that means he still has some time to realize Yasuho's peril and come for her. It's also possible that during his next encounter with the head doctor, he will finally realize that the branch isn't with him, and will end up coming to the Higashikata estate anyways.
3. Mamezuku. Perhaps more unlikely given he's not exactly best buds with Yasuho, but seeing as how jail bars and handcuffs should be a joke to Doggystyle's ability, he could escape and join the fray.
4. Joubin. I mean, that's a given.
5. Tsurugi. Seriously, what happened during those three hours?
6. Mitsuba. She's unlikely to be antagonistic towards Yasuho, and it's not unlikely that she could help her out like she did in the Doctor Wu fight.
As for the X-factors:
1. Akefu Satoru. Dunno if Josuke is gonna retire him at the TG University hospital, but there is a chance that he could survive and come to the estate.
2. Tooru. Seriously, WHAT exactly is this guy?
3. Kaato. Considering she knows the ins and outs of the estate, it's possible that she could also come into the estate and join the battle for the branch. Alternatively, she could maybe be the another world DIO of this part and up taking part in the post-endgame of JoJolion.
Of course, JoJo being JoJo, predictions can only go so far, but I thought I'd at least make an attempt.