Jeff If you stock 3"-4" tilapia consider that a good number of them will be fish food for the larger LMB, CC and maybe WE. If your predators are still small (less than 13"-15") in your new pond then 3"-4" tilapia stockers should have good survivability.
I think water temperature plays in to this equation too. If your tilapia are slugish, yes, larger predators can be an issue. If the pond temp is warm enough, tilapia can escape many preditors pretty easily.
