For FSK demodulation I suspect you would want the loop to distinguish between two different frequencies that are in the lock range of your PLL. One of the two frequencies represents a logical 0 and the other frequency represents a logical 1. The output of the loop just re-produces the input...
Here's a pic of my functional remote. Note that the LED circuit is not necessary and is absent from this unit. This one has a different P/N on the IC, however my other unit matches yours (SC370524P).
Waveforms below. Top waveform is output of the IC applied to the base of the NPN...
Debugging one of these now. Two actually. One works, one doesn't. The cmos chip produces a repeating train of ten pulses which is sent to the base of the transistor. The dip switches determine the width of the pulses (single wide or half wide). The transistor on my remote is MPSH10 NPN...