Do you have voltage at the coil? If that's there then when you press the flipper button one side of the coil should go to ground. If you have voltage at the coil and one side does not go to ground then you will need to go back to Q10 and then go back from there. The schematic shows F901 as well but you said all applicable. If there is no voltage at the coil then check voltage at J901 pins 1 and 5? Maybe the flipper opto is not firing? Doubt it but just make sure.

So no voltage to the coils. Do you have voltage at connector J901 pins 1 and 5? If yes then do you have voltage at connector J907 pins 1 and 7? If no then it's either F901,F903, C2 or BR1. Sorry, I mean from GND to the pins 1 and or 7 since 1 and 7 are the same side. BTW the upper left flipper doesn't work as well, correct?

Yes, if the upper left is working then we know that BR1 and C2 are fine and F901 is allowing the voltage to go to the upper left flipper. Since F903 and F901 come from the same source then either F903 is blown or you have an open from F903 to the lower left flipper coil. Since shorted something on the coil you most likely blew the connection from the wire to the coil? Do a continuity check from the coil to the fuse F903. Or better still check the continuity from fuse F901 to connector J907 pin 7 and then to the flipper coil. Do you have continuity at each of these stages.