Mr. Brewer puts a lock on the basement door, drilling the basement door shut. If he did that then he wouldn't be able to continue working on the experiments.
The final premise, where Margaret and Casey cannot choose which "father" to spray with the weed killer makes no sense. As one of them is human and would not be affected by weed killer at all, they could simply spray both of them rather than waiting to choose one.
Dr. Brewer wears a blue hat with a 'S' logo on it, but is not affiliated with a baseball team. Even though Casey tells him that he hates baseball.
Mr. Brewer puts a lock on the basement door, drilling the basement door shut. If he did that then he wouldn't be able to continue working on the experiments.
When Marget and Casey go looking trough the papers on the counter, Marget mentions about the 'plant food' that Mr. Brewer tried to get them to eat in the previous episode, yet in the previous episode she didn't know what it was. But now all of a sudden she knows what it is.
The phone number that Mrs. Brewer gives on the answer machine is 555-0101. This is obviously a fake number. Also, there is no area code given.