I saw something a while ago on DoC about this, and went to go read about it
there in addition to your reddit link. I'm not sure but I suspect if you opened a joint account, the only things that could be moved into it are accounts that are also held jointly, i.e. joint checking, joint savings, joint brokerage, but not IRAs since those are in one person's name only. I mention this since you said "almost all of it is just P2s." Then, I think you're right that he'd need the CSP. I missed what you meant by "a long time to wait." Does P2 have to wait til next year to get the CSP? And are you waiting for an increased offer on CSP like the one that popped up briefly this year? That one had a pretty high spend! Or waiting for a higher Sapphire banking bonus? On DoC it said the 60K UR was higher than they were expecting.
I wonder if getting the Chase bank bonuses this year disqualify one from getting the Sapphire banking bonus. I read that recently Chase updated the terms of the banking bonus to q two years instead of one. If that carries over to the Sapphire then I'm out since I got the 300+200 bonus earlier this year. A comment on DoC said they were told they would be ineligible bc they got a $300 bank bonus. And my P2 doesn't have a CSP or CSR anymore; I was planning on having him get the CSP a 3rd time in Dec but then Chase went and implemented the 48 month rule.
If you haven't already done a Chase bank bonus this year or last, I think the current $600 one is easier (lot lower minimum!) than the Sapphire bank bonus.