Not sure what is the behaviour under Android, however, under Leste, what happens when you enable mouse integration in the VM is that mouse events are generated by a pseudo TS device, Leste detects that and hides the cursor. If you disable mouse integration, mouse events are generated through pseudo mouse device, Leste detects that and makes the cursor visible. We did it like that so when you touch the screen on a real HW (phone), cursor will be hidden, however, if an external (relative) pointer device is connected and used, cursor will be made visible.

Bluetooth support is planned, however, there are higher priority things (like phone calls) on the list.