Gearbox remove questions (ernie?)

Unfortunately yes.

The reason you need to drain the oil is because you must remove the feed pipe that runs along side the gear box to the oil tank. The flexible hose on the back of the pipe only goes to the tank. The rest of the pipe is solid to where it attaches to the engine block. So if you where to try and lower the gear box without removing the pipe you will bend it. There isn't enough clearance to move the gear box to one side until it has dropped out of the upper support mounting bracket on the sub frame. So that is why you need to drain the oil and move the pipe out of the way.

No.

The engine is held in place by the motor mounts.

You loosen the 6 bolts on each inner CV joint attached to the gear box. You don't need to disconnect the CV joints from the wheels, only from the gear box side of the half shafts.