how can I get each slave to retrieve a unique address from the master node?
how can I get each slave to self-allocate a unique address?
how can I send each slave a unique address from the master node before it has an SPI address allocated to it?
All this is moot until you explain how you are going to connect them, because SPI is not by nature an addressing bus and if you use logic to get 32 CS signals then the Arduinos don't need to know any address in the first place.
Rob