Ah I see what you’re saying now – I misunderstood what you were pointing out (thought it was that the SQ-5 couldn’t handle 48 inputs). You’re right that the setup described still needs 48 physical inputs (only exception would be inputs coming over usb).
When OP said 32 inputs with a copper snake I assumed its an SQ-7, which could be paired with the DX168 or AB168 you mentioned for the 48 inputs.
Other combinations that could work for 48 inputs would be SQ-6 + AR2412, or SQ-5 with multiple stageboxes.