Entirely random question... *How* did you manage to create biome "themes"? As far as I can tell, biomes are hardcoded into the game... Am I misinterpreting the description of the mod? Does it not add different "themes" for good and evil biomes along with general expansion?
Basically it makes use of the hardcoded biomes to create, granted climate-based by necessity of how the game works, themed biomes.
For example, unlike say wormy tendril or glumprongs which can potentially be found in
all non-frozen evil biomes, you aren't going to find stuff from the flesh-marshes (evil temperate wetlands) in the spore swamps (evil tropical wetlands.)
Should things spawn (which they aren't guaranteed to do unfortunately,) you're going to have two very different results, with meat moss and veins for grass, bone and meat-based trees and more body-horror-y creatures in one, and fungi-based monsters, giant mushrooms, and general rot-themed stuff in the other, with no overlap unless those biomes somehow overlap through sheer random coincidence.
However, as mentioned, these things aren't guaranteed to appear, which can happen even in the vanilla game where you roll a world where "good" or "evil" biomes are entirely mundane and boring with the only difference being some vermin and a few creatures added to the rotation of standard wildlife and depending on settings, some crappy weather to stress your dudes out.