I'm not clear about this...

The modified evdev_drv.so is not safe? It might cause your keyboard to stop working? Or the driver is safe, but you might lose your keyboard if you make a mistake?

Can you install the new driver before pairing the mouse, or does the new driver interfere with the pairing somehow?

I'm asking this because it would be fairly simple to make a package that installs the new driver and enables BT HID support, but I don't want to do that if the driver may cause serious problems.