There is no speakers on this Pi Deck but if I need sound I either use bluetooth headphones or connect it to my Alexa which works really well.
I stuck a magnet (harvested from an old HDD) to the rear of the keyboard so that the mouse is held in place when not in use.
I use an inline usb power switch to turn it all on/off, I may add another just for the monitor if I am using the Pi headless.
Hi its lasts a couple of hours, I have never run it right down so I don't know exactly.