The eggs and toast became inedible, respectively shriveled and stone-hard after a mere half an hour, because of the radiation and probable heat in the air.
The family's silhouettes show them in the garden, working, playing—they had no idea about the bomb until it incinerated them.
In the animated Soviet adaptation, they were nuked while they were asleep.
In the animated adaptation, a fake window displays a video of a lovely day to conceal the harsh view, but it seems to have been playing even before the nukes hit. Also, the work clothes of the family resemble hazmat suits. How bad was pre-war America? Could have the nukes essentially put an end to an already Crapsack World?
The very violent and destructive reaction of the robot when the bird flies into the window in the animated adaptation would have led to at least one, if not several, deaths or serious injuries. The first blow the robot aims at the bird sends the elderly grandma's wheelchair slamming into the wall, for starters.
If the family falls out of bed first thing in the morning, how long has it been since the bomb hit?
Presumably the makers of the short film decided that we saw it the day after the bomb went off, while they were sleeping. But that just raises further questions.
Also from the short: Why does the robot send them to work on New Year's Eve?
Plenty of people have to work on New Year's Eve. It's rather odd that the children would be going to school, though.
Maybe because if the parents are working, school would serve as childcare?
If they were close enough to the blast to be reduced to ashes in the animated short, how were other things like the doll, blanket, and watch not scorched as well? Additionally, the EMP pulse from the blast should have severely messed with the house-bot, if not destroyed it entirely.
Presumably this futuristic society was able to harden some of its appliances? The house itself in the animated short is still standing, so perhaps some of its entities could survive compared to the unfortunate people.
The original story was written in 1950, predating microchips and transistors, and the vacuum tube-based electronics Bradbury would have been familiar with at the time are EMP resistant. As for the Soviet adaptation, their electronics were always behind the West (particularly with regard to consumer products).
Why would a Smart House designed to cook and care for a family, including vulnerable young children and an elderly woman, not be equipped to detect the residents' life signs? You'd think a system sophisticated enough to cook breakfast would also be tasked to call an ambulance if the residents' pulse or breathing sounds were interrupted or distressed.
When the Smart House senses that the dog dies, it's phrased in a way that would suggest that it reacts to decay rather than lack of vital signs — and the nuclear annihilation didn't leave a body. This just brings up further questions, like why the house would continue to operate despite it clearly being a danger to itself.
If the dog belonged to the family, why didn't the house recognize it and let it inside?
