There is no documentation for special scenarios with the 64S involved available at this time, so I can only guess... What you try to do seems to be possible in Stagebox Mode, because you use the console's screen or UC Surface to set the network routing. Input channels 1-32 of the 32R must be routed to channels 33-64 on the console and auxes 17-32 must be routed to physical outputs 1-16 on the rack mixer. I don't see any reason why this should not work. In Monitor Mixer Mode the rack mixer needs to be connected to a router, because you need remote control (UC Surface).
But there comes the question into my mind why you try to set up such a complicated system. In DAW mode you can use the console as 32 channel interface and (more than) 64 channel mixer for Studio One. A rack mixer is only needed to expand the numbers of physical input and outputs, not for routing tracks between computer and console.