When Maxwell jumps in the pool, the gray in his hair washes out.
When the dog napper is watching his accomplice approach Maxwell, he is looking out the side door of the van. He then leaves the van via the back door, and then Maxwell runs up from the back of the van, a completely different direction than he was being watched from seconds before.
Even though Val is not the smartest, she should've known the chocolate Fran gave the dognappers was the chocolate ex-lax Yetta gave her. Val was with Fran and Yetta when she gave it to her.