The Yeerks are scrupulous when they can't be somewhat simple in their plans but always cold and methodical with their designs. Their Empire's sole purpose was to spread throughout the universe, adopting what was convenient from their enslaved species and using it to strengthen their own, so they can continue to spread.
Anything less than that on Earth, would have been 'living as a human', and it simply isn't the way they run things.
The reason I said things like the human media would have been removed, is because the Yeerks already have the technology that surpasses all those things. I am not even sure suburbian houses would have been kept. Indeed, I can see them building cities with high-as skyscrapers that are triple the size of the human's tallest one. Accomodating Controllers sort of like the walls in a hive of bees. This would be more practival in a Yeerk-owned Earth and they certainly have the tech to do it.
Not even hospitals, heck, they've got their own equivalents.
And the human-made landmarks wouldn't be used, unless they could make some political statement against the human civilization (like
Baranth stated above), to put themselves up or bring the 'human spirit' down within the individual hosts. Keeping in mind that a landmark in America would mean nothing to a landmark in Botswana. If they weren't destroyed, they would have been left to nature. The city of
Petra,
Macchu Picchu,
Uluru would just be irrelevant rocks on the Earth's surface and the
Parthenon,
Great Wall and
Stonehenge would just be derilict human constructs, IF the Yeerks didn't feel like testing their Dracon cannons.
And, though I think the Yeerks seek some sort of entertainment, they are also some highly-advanced species with other concepts of entertainment. So, I don't think we would see the Yeerks sporting any sort of world cup or playing uno when they were stuck indoors in the winter cold places, just because they would need to clamp down on their human hosts' esteem. They wouldn't
really need to tame their hosts, even if they're voluntary ones at this stage.
The only thing that would save some of the animal species of Earth is if they could use them on other planets they intend to invade. Much like Visser Three used his
Veleek on the Anis, or Visser One with the tiger sharks in the
Leera campaign. The Yeerks could win over the Andalites by sheer numbers, indeed, but I suspect, with the strong possibility of Visser Three would being in the reigns, following his success on Earth, he would have thrown in mind-controlled Earth predators let loose on the Andalites for some of his sick distraction. A crockie in their waters, a golden eagle in their air, a funnel-web spider in their scoops all would provide decent psychological damage.
Do you think they would go ahead and try to turn the moon into a Kandrona? Or going with their North Pole plan?
The North Pole Kandrona idea revolved around the Infiltration factor, me thinks. With that gone, I don't really see why the Yeerks would do their artificial sources of food any differently than in their other enslaved-planets.