Originally Posted By: hybrid8
Turning ON or OFF either BT device will cause the Mac to wake, making it seemingly impossible to power down both devices AND put the Mac to sleep.

If you want to disable the ability for bluetooth devices to wake the system, the option is in System Preferences, Bluetooth, Advanced.

Originally Posted By: hybrid8
One issue is when wanting to carry the Mac elsewhere in the house. If I turn off both inout devices the Mac will wake up as I'm picking it up. If I leave one of the devices on then the Mac will connect/disconnect to/from it from elsewhere in the house repeatedly.

Is this the only reason you are powering them off? An alternative solution here may be to just leave them on, letting them go into their low power state automatically when the system goes to sleep. And if you then take the laptop elsewhere just within range, but not wanting to use them, click the Bluetooth menu icon, choose the device, and click disconnect. The Mac shouldn't reconnect to them, unless you walk over and press a key/click the trackpad.