Instead of a Servo, this could be very easily be done by the combination of a spring and a linear magnetic actuator. The downside is, that the setup needs a minimum weight of the item to overcome the closing spring.
Upon detection of the hand, the actuator retracts the locking bar and the weight of the item pushes the door open against the spring. As the item falls off the door, the spring pushes the door back to the start position. Once the door is back in position, it triggers the actuator to lock the door again.
Instead of springs, a second actuator could be used: a linear actuator could pull the link back via a tilting link, then return to its extended position afterward. The actuator's connection to the link rides in a slot, so the gate can fall freely. If the slot is replaced by just a hole, the actuator could also act as the lock.
A turning actuator could push the lid closed by simply doing about a quarter turn and having a peg that presses down the lever to return the gate to the position. And, if the resting position is down, it might even act as the Lock in the bottom position. With the tab chosen as the right length and bend at the end, a full rotation of the motor would release, then close the hatch with just one servo.