I just presented a circuit to start with and please remember that simulation based on typical and ideal models doesn't reflect 100% what we may have and get on the breadboard (or PCB).
Since the frequency is relatively low, a standard general purpose NPN transistor as BC549 (or equivalent) likely provides higher gain than of BF199. In case you will use another transistor, the resistors R12 and R14 for the DC bias may need to be changed a bit in order to get the optimum bias.
Also the ratio C13/C14 is important. For high C14 (low ratio), the selectivity Q of the LC circuit will be high too (loaded less) but the positive feedback decreases.
About driving the MCU input pin, the current of the clamping diode (as 1N4148, low capacitance) from the pin to MCU Vcc (its cathode at Vcc) will be about:
(9-5.5)/10= 0.35mA.
Even if most of this current passes in the MCU diode (in parallel internally), it won't affect the pin functioning.
On the other hand you can use a zener diode instead (between pin and ground) but you need to choose its voltage as 5V6 (perhaps 6V2) to get about 4.5 V at the pin since the zener current is very small limited by R17 (for standard 400mW zeners, the typical current to get Vz is 5mA).
It doesn’t matter how many times we fail while designing a new project as long we end up with a good practical one. So the only serious failure happens when the project has to be dropped for ever
But even after every complete failure, we have a better chance in choosing another project which is more realizable. For instance, I cannot count my failures (silly and serious) before launching any new product. The irony is that those who use my products think I am genius
Kerim