What ever happened to acid rain? I think if the acid rains killed off much of humanity, they should melt all the zombies and wildlife, trees, houses and everything that can dissolved by acid, as well.
For being a xenophobic, highly reactionary, well-armed populace in this society, I wonder how there are zombies at all, seeing as a basic survivor with a basic rifle and basic weapons or a compact sedan can safely eliminate any number of zombies, fungus, ect and clear a whole town alone, let alone a whole police department, national guard unit, robot armies, ect.
How does the whole blob-infection thing work again? If it's in the drinking water, it's safe to assume every survivor and creature everywhere is infected and will reanimate on death. If it can survive the processes used to service the tap water supply, it can survive in any source of water, so everything in New England has done caught da blob.... Which makes me wonder, if a blob-infected woman gets pregnant, does the kid get the blob, too? Gets born and dies with this alien thing in it forever, doesn't that destroy any chance humanity has to win? How about a miscarriage? The fetus goes zombie-mode?
Acid rain was cut out when weather got reworked. Bringing it back isn't as easy as flipping back a switch, because now we'd have to consider the implications (why don't animals care about being showered in acid?). When we get some more advanced AI like shelter seeking behavior, acid rain would be cool to have back.
Lore suggests that the initial invasion wasn't just zombies, but hardcore stuff like shoggoths and flying polyps. Then all the really bad stuff died due to being unadapted to live there.
Kid probably would get the blob. Humanity doesn't really need to "win", only learn to cope with all the dead reanimating. Cremate everyone instead of burying, for example.
Fetus wouldn't reanimate because it's too small. Lore doesn't state what happens to small blob-infected things, only that they don't reanimate.
For technical reasons, small blob-infected things just rot and disappear. Later on (when human, moose, bear etc. corpses reanimate), small blob-infected stuff could just turn into small blobs or something like that. It would make sense for the blob to eat the surrounding body when it is no longer keeping it contained.