#4 If the rear of the machine abuts a wall, can I remove the water tank by lifting it vertically (like the 840 or 870), or must it be moved rearward?
The tank of the BES920XL Barista Express would not be accessible with the back of the machine kept against the wall. Removing the drip tray will give you access to the adjustment wheel that lowers and allows the machine to be moved, swung out, or adjusted as needed, including giving you access to the water tank. As there is a press-open cover on the top front of the machine that allows water to be added to the tank without moving the espresso machine, the only time it would be necessary to actually gain access to the tank itself would be to change out the water filter or when doing a descaling of the machine