Maybe this will work: Go to lines 564 and 581 of the script section WindowAndTilemap and replace them with this line:
Code:
spriteZ=(@priorities[id]==0||!@priorities[id]) ? 0 : zOffset+@priorities[id]*32
To answer BlueEew's question, I will make the species count practically unlimited; or more accurately, as high as the highest numbered species on the pokemon.txt file.