2 things to check, do the front plugs have spark and does the tachometer twitch or move when cranking to indicate the computer is recieving signal from the crankshaft position sensor? Also while you have the timing belt exposed can you tell if the timing marls are inline to be properly timed?
Yes the spark plug needs a path to ground, either an inline spark tester needs to be connected between the plug and coil or plug needs to be removed and connected to exposed coil and grounded to the engine or something metal on the car to see the spark. How did the plugs look? Were they black with fuel fouling?