When Norah chases after the kitten, there is a small table and a cat statue on the porch. Later, when the house is burning at night, the table and statue are gone. A subsequent scene of the porch in flames has the table and cat statue back again.
When Norah and Lynn are at the party, Norah passes the joint to a guy next to Lynn. She does not get it back, but she can be seen smoking it in the following shots.
When Amy Adams' character hands the $10 bill to Emily Blunt's character for babysitting, the bill is obviously fake. The portrait on the bill is not of Alexander Hamilton, but appears to be president James Buchanan. The figure in the portrait on the bill used in the movie is facing right. All portraits of Hamilton on the $10 bill have been facing left since 1929.
When Rose and Norah clean up after a suicide committed by a "Mr. Davis", they enter a room where several rosaries and a crucifix are hanging on the wall, indicating that the couple is Roman Catholic. Since Catholics believe committing suicide irrevocably sends you to Hell, it is extremely doubtful that the husband would commit suicide.
However, not only it is false that committing suicide "irrevocably sends you to Hell" even from a catholic point of view, but the mere thinking that a catholic will not commit suicide because of their beliefs is highly delusional.
At about 54 minutes, when Oscar is crossing a street, a microphone can be clearly seen on the top left corner of the screen for a few seconds.
Norah's accent changes often.