Truthfully I don’t think we should even consider settling any body with a complex biosphere. We’re going to have to search for a very long time before we find a biosphere anywhere near as complex as Earth’s. You probably have to scour entire galaxies before you find another world with covered in a biosphere as rich as Earth’s. These worlds will be so rare and so far away, that by the time we can reach them, if ever, we’ll have already become experts at living in space. Hell, by the time we even attempt interstellar colonization, the vast majority of the human population likely won’t even live on a planetary surface. By the time we reach a true Earth twin, humanity will have become experts at transforming the deadest of dead rocks into living worlds. (Or just forego the idea entirely and use planets only as sources of raw materials for space-based habitats.)

I see no reason to ever colonize and exploit those rare Edens. Explore? Sure. Comb the organisms there for useful genetics and compounds? No problem. But actually settling en masse? Just leave them alone. We can afford to leave .00001% of planet’s untouched.