We'll go over speed bumps of first figuring things out but in the end we'll be just fine, they're already bought in to figuring it out.
I still think the best idea is to stagger one (Harden) so that one of them is always on the court at a time. Whoever it ends up being has free reign to do whatever with the second unit, luckily all 3 are decent to above average passers. You can keep sprinkling Joe's minutes in with the 2nd group as well and space the floor even more.