I'd be looking hard at the solenoid positive that runs out and daisy chains to all the solenoids. 

Your solenoid voltage looks to be present and correct as you've measured it on the power board and also the flippers work. I haven't got a schematic in front of me but I recall the flippers go through a relay on the driver board.  The solenoids have the positive looped around to each coil (the positive will have two wires to it) and the individual drive transistor for a particular solenoid switches a connection to ground.  So if none work, the common path is the positive loop wire - I'd look pretty hard at it and the playfield to head connectors that carries it.