Only Homer and Abe attend Mona's funeral, along with Seth, Munchie, and Mason Fairbanks. While the rest of the Simpson family is no where to be found.
The Simpsons family returns from the Stuff n' Hug store in the evening, but as Homer walks into the kitchen, spinning the "Defender", he stops next to a window and the sky outside is much brighter.
If the recording bears would play the message only if you would press their button then how could they offend Homer (by saying whatever had Bart recorded) just when he entered the place without someone pushing their buttons?
Homer is surprised that his mother is alive, but in while reading the newspaper solving the "message" IMOK (I am OK) he alredy had a theory that his mom didn't die while the prison bus dropped off the cliff. However, it possibly was due to the fact that Homer didn't anticipate her coming back to him.