After configuration with a PC (not tried without a PC), you can scan via Wifi without a PC into your favourite cloud (tested with onedrive and Google drive)! For the USB I think it is not possible.

As Colab says, this seems impossible, as the machine is controlled by the PC.

As far as I know not. Even to send a scanned document by email, the computer must be switched on and reachable by Wifi (or USB?). The scan automatically opens an empty email with the scan attached.

Good question, but I haven't tried it yet.