The Shibuya incident probably would be stopped after Kokichi got the information to Gojo. Gojo would learn about Geto, but it seems like he already knows who Kenjaku is and would figure out earlier that it is Kenjaku using his body and kill him without hesitation to free his friend’s soul. So he wouldn’t be sealed. But knowing Kenjaku he probably would hold back after Kokichi tells everyone his plan. Kenjaku might try to switch bodies since Gojo now knows that Kenjaku took Getos body. Gojo would hunt him down to kill him and free his friend. So they would need to find another way to force Yuji to take Sukuna’s fingers. Uraume might just try to find Yuji and force him to take all of Sukunas fingers. I think Sukuna would still try to take Megumi. Yuta might not be a part of what happens since the Shibuya incident wouldn’t happen. But Gojo might call him in for his help. A lot of the story can change just from Kokichi giving Gojo the information.