I was trying to do something similar. I believe that there is a way to keep crappie from stunting in small ponds, but most people are so fixated on LMB/BG, that there is little research on other fish combinations.
Unfortunately, my pond got overrun by black bullheads right after I stocked the crappie, so I have other problems at the moment.
As for the tilapia, I am setting up 75 gal aquarium in the garage to keep them alive through the winter.
