other thing, as you might have noticed from that save, it took a while since something spawned, especially the further away from center you got.
when running your mod with rampant, I think >90% of all enemies spawned(on top of ore or not) were from rampant, only if by chance a vanilla biter nest spawns, which itself has to spawn on top of ore, will it spawn infused nests.
so maybe make their already given effects stronger or give them more effects, since they are extremely rare(with other mob spawners)... or include "aliens" from rampant, bobs enemies, etc..
uranium: an aura which damages enemies when near them, give their attacks a damage over time effect.
coal/oil: include the spawners in polluting the area(which will increase the evolution, since it's pollution), make the biters or spawners explode/burn when attacked by incenary weapons or explosives.
iron/copper: armor piercing attacks
stone: more resistances
and I would make them more distinct, maybe bigger than the usual biters at the current evolution factor.
with natural evolution enemies there is no way in telling which one is which: https://imgur.com/a/YrXmSWJ
Edit: maybe I should have made a new thread instead of posting this here