Well #12 is an o-ring, so without that you're going to most likely have a leak around the drain plug. As for the rest #8 is an oil pickup which is where the engine is supposed to pick up the oil from the crank case to send it through the rest of the motor, #9 is a filter screen that is there to keep dirt and garbage from being sucked up by the pick up and pumped through the motor, and #10 is a spring that puts pressure on the screen and keeps it in place.
So what will happen: The motor will not be picking up oil from the certain depth in the crank case that it was designed to, which means you will probably need to run more oil to compensate for oil slosh or be prepared for catastrophic failure in the worst case scenario when there is no oil getting pumped through the motor because it was not picked up. And for the rest when it is pumping oil, it is not the cleanest and is pumping garbage until the oil makes its way to the oil filter.