At breakfast early on, Dad pours Emma a glass of milk, which in a second shot is seen full on the table. However, the bottle in his hand is also almost completely full, the lack of milk near the top of the bottle is what is normally there when one buys a fresh bottle of milk, and certainly, given the amount of milk left in the nearly full bottle, not enough is missing to have filled the glass to the full.
Emma turns on the gas, then lights all the burners on a stove with coil burners, which don't run on gas.
What Emma was attempting by turning on the electric stove in addition to the two gas fireplaces is unclear, but the auto-ignition temperature of natural gas is 1400F, and the large burners of an electric stove-top can reach between 1472F and 1652F, so if the gas had reached sufficient amount and the burners had gotten hot enough, an explosion or fire would have happened.
A cat would never have drowned in that fountain. Cats are great swimmers and that fountain would have been no problem for one to climb out of.
The possible error about the associate's area code not matching the purported physical location may be obsolete. In theses days of cell phones and VoIP, the phone's area code may not match the current physical location. Besides, this movie was filmed in the Vancouver area, so all of the cars with Washington State license plates were imported anyway.
When David calls Dr. March, he hears a voicemail referring to her associate's phone number with area code 914. That area code is for Westchester County, New York, but all the vehicle license plates are Washington State.
10-year-old Emma could never have removed a full-sized hornet's nest from a garage's upper rafter by herself safely, without being stung, THEN moved it down the street and into Mrs. Ellis' car--which was LOCKED at the time! How did Emma get a hornet's nest into a locked car?