When Pinky goes to seal the mouse in its hole, there is no mousetrap on the floor. In the close-up, the mousetrap is on the floor right by the hole. Then, in the next wide shot, the trap is gone again.
You don't need a fire to ignite gas, a spark will do the trick.
The wall calendar shows that there are 31 days in February. February only has 28 days, or 29 during a leap year.