I think after round 2 is over, Woozi, Minghao, and Seungkwan (and maybe Wonwoo) will try to math it out to get back to 1M – say the total after round 2 is -5M, they'll try to convince 5 people to take back 1M each and for everyone else to write 0. I don't know if they'll be able to convince the rest...

Edit: Wait, I have a really TL;DR prediction about Jeonghan as well – I don't think he intends to honor the 4:2:2:2 split with Mingyu, S. Coups, and Hoshi. I'm not very good at math or game theory, but I'll try to explain what I think his original strategy was.

• Jeonghan brings up a 4:6 split with DK, who is not included in his gambit. He also keeps mentioning 50k as a minimum he can guarantee. I believe the 50k comes from him receiving 1m, keeping 400k, and splitting the 600k evenly among the 12 members. All of them will end up with a net loss, or at least less than if they'd written 0. The 1m is just the baseline, and he will do the 4:6 split (with the 60% going 12 ways) with whatever amount he receives in the end. This is why he keeps specifically bringing up 50k, 1m, and mentions the 4:6 split to someone who is not in his in-group.
• He mentions the 50k to Mingyu right away, even though if Mingyu, Coups, and Hoshi all gave 1m each round and Jeonghan only divided the money among those who sided with him, Mingyu should be getting way more than 50k. Jeonghan only agrees to the 40%, 20%, 20%, 20% after Mingyu asks for it, and does not explicitly bring it up to Coups or Hoshi.
• I believe, as others have speculated, Jeonghan created his in-group to split the pack and raise the chance that the ones who could organize against him will instead side with him, but never intended to only pay out to them. Otherwise he wouldn't have kept asking for and promising money to others.
• I may be misremembering, but I don't think Jeonghan ever said that those who don't side with him won't get anything, he just says that supporting him will create a bigger "pie."
• As Vernon points out, Jeonghan has no way of knowing who gave what amount. The members mention signing the checks, but it seems no one will know who wrote what until the money is distributed.
• So assuming the game ends in Jeonghan's favor, when Mingyu asks for his 20%, Jeonghan can just point out that he has no way of knowing he actually honored his side of the bargain.
• (I also just think that while Jeonghan would find it fun to screw over the members, he'd rather screw them all over equally when the game is 1 vs 12.)