Regarding the First bag/Last bag scenario it can be done and is done every day by the Ryanair baggage handlers.
From chocks in to bags on baggage belt takes your average ryanair crew about 10 mins, sometimes quicker. 25 mins to turn the aircraft around entirely. The ryanair model is extremely efficient.
Now....Ive seen another set-up with another airline where because "its Not my job to drive the truck" we dont get a truck out to the aircraft for a while. Eventually a truck arrives, bags are offloaded and driven into the baggage hall.
The truck driver walks away because "Its not my job to offload the truck". Eventually handlers arrive to offload the truck but the truck remains sitting at the belt blocking everyone else because "its Not my job to drive the truck out of the baggage hall".....Get the picture ?....15 minute first bag !!! No way if youre company uses this model. When you have numerous airlines using the same belts this leads to chaos, especially during busy periods.