Wonder if - lacking an order top stop from the FCC - I could occupy a frequency and ultimately claim squatters rights or adverse posession on the frequency if someone eventually licenses it.
Adverse possession traces its roots back to the Homestead Act of 1862. I'm not sure how exactly you'd claim you were making a residence out of a radio frequency.
The FCC hasn’t historically supported that. One of the early FM pioneers was ruined when Sarnoff lobbied to allocate his frequencies for another purpose, for example.