Question: How did they climb the grain silo without making noise? Why did the silo door come off its hinges?
Question: Where is the mailbox with the Abbott's name on it?
Question: Why are they using so many candles/gas lamps when they have electricity, esp in the Monopoly scene?
Question: Why did the dad sacrifice himself when all he had to do was toss a hard object at a metal object to distract the monster?
Answer: Because there's no guarantee that would work...the creatures don't just go insane for any sound they hear. They've already discovered there are humans (or at least, something they can kill/eat) within the truck, so just hearing some random noise might not be enough. Instead, he makes it clear to them that he is a human and vulnerable, so they switch their attention to him, knowing that they can get him with less work than it would take to rip the truck apart.
Question: How would a deaf person know whether they're making a noise? Was the daughter constantly monitored, so she didn't inadvertently break a branch, slap her hand on a table, do anything that makes a noise?
Answer: She's deaf but is fully cognizant, educated, and old enough to be aware. Just because she cannot hear anything does not mean she doesn't understand what makes noise and the need to be quiet at all times. She also normally uses a cochlear implant that allows some hearing, but due to the invasion, it is currently unusable.
Question: Where is the electricity coming from? Surely all power plants would be out of commission after more than a year. Gas powered generators would be too noisy and alert the creatures.
Answer: There are shots in the film in which we can see solar panels attached to the roofs of the buildings, so this is where it comes from.
Question: Why don't they just abandon the place and go to somewhere safer?
Question: If they were still uncertain of their safety, why was the baby no longer under oxygen and his box with its lid? Especially when Lee had to leave them alone to look for the other kids.
Question: How do the alien creatures orientate? They're blind but sensitive to noises, so I guess it is supposed to be some kind of echolocation - but first, echolocation is not a way of "seeing" your environments constantly, especially not suitable for running like crazy in a forest full of trees and obstacles. Second, by using echolocation, they should be able to locate moving objects even it's noiseless. So how?
Question: Who is running the power plants so that they can turn the lights on? I work at a power plant and it is not quiet.
Answer: If you look closely at the background in one scene, you can see solar panels attached to the roof of the home, providing them with energy. Additionally, the original script also mentioned that the family also used generators that were located underground so the noise would be muffled, though I don't believe it's mentioned in the film itself.
Answer: Electricity would be a precious commodity, to be saved for essential purposes/emergencies. Why waste it when you have candles/gas lamps, which are far less resource-intensive?