Is inverted flight possible under these conditions?
Yes, based purely on the wing shape an airliner could fly upside down and maintain a straight inverted flight. The lift of the wing is a function of the vertical angle of the airflow, the angle of attack. 

Image source

The picture shows an airfoil pointed upwards, but the same forces apply when the wing nose point downwards. Then turn the picture upside down, and you have lift pointing upwards again. 

The situation is valid for an asymmetric airfoil as well, the only difference being that it provides lift at AoA zero. Zero lift is provided at a slight negative angle of attack, so the aircraft nose will be further up when inverted, still below the stall angle though.