74XX14 is a Schmitt trigger. A Schmitt trigger has hysteresis. Google "Schmitt trigger" and "hysteresis" if you need more info. The circuit I posted is an oscillator, and the inverters ("gates") must have hysteresis, or the circuit will not oscillate. There are other Schmitt triggers you could use, but it is important that they are specified to work down to 2 volts. 74HC14 is one of the common ones. You might be able to use 74AC14, 74AHC14, etc. I haven't checked their specs.
Here is a good article about Schmitt triggers.
The circuit you originally posted works by charging the cap up until the voltage is high enough to allow current to flow through the series combo of the base of the PNP and the LED. When this occurs, the PNP starts to turn on the NPN, pulling even more base current through the PNP (via the resistor), which is a regenerative process. The collector-emitter voltage of the NPN rapidly goes to near zero, activating the motor. The high motor current rapidly discharges the capacitor, and its voltage goes so low that the regenerative PNP-NPN switch turns off, and the process starts all over.
My idea is that, somewhere during the capacitor charging cycle, the oscillator will start (probably around 1.5V). It will rapidly connect the cathodes of the LEDs t0 GND alternately. The frequency of the oscillator, the time when it starts, and the time when the cap voltage reaches the regenerative threshold will vary depending on incident light, so in theory, either circuit could be enabled at the time the threshold is reached.
As I said, this may not work due to threshold mismatching between the two circuits.