Can you change MacBook Bluetooth ID so two os can be seen as different hardware?

Automatically pair the same set of Bluetooth Devices, while booting MACOS from 2 independent partitions:

(Each partition contains the whole MACOS)

Use identical Bluetooth.plist file on multiple partitions:

I presume that your partitions both contain the entire MACOS, and they do not share any system storage space. I recommend simply to:

1. Setup all the Bluetooth devices after booting with partition 1.
2. Copy the ~/Library/Preferences/com.apple.Bluetooth.plist file to a USB drive.
3. Boot from partition 2.
4. Replace the partition 2 ~/Library/Preferences/com.apple.Bluetooth.plist with the file from the USB drive.

Let me know if this worked out for you.