Does circled transistor or capacitor value cause buffer stage to stop transmitter from working?
I think that your buffer is killing the osc meaning that you will get no signal or it is capacitively detuning it downwards making your frequency way lower than it is supposed to be .Remember that the CE BJT has a  low input impedance at your collector currents .Your osc has a relatively high impedance on the collector where you are taking the base drive power from .There are lots of ways to cure this .You are spoilt with options so I will state some fixes.Take the drive from the emmitter of the osc BJT adjusting CX for feedback if needed.Consider an emmitter follower for the buffer .Consider a JFET buffer .