While the family is at the island, Ferb gives a monkey a shower because "it had to be done". This is one of the activities the intro credits sings about.
This is the second appearance of Marty the Rabbit Boy after "Flop Starz".
When the kids all run up to hug Perry, if examined closely, Isabella is hugging Phineas instead. Baljeet also appears to hug Ferb, but when the kids moved right, Baljeet's arm is shown to extend further.
During "Come Home Perry", Candace mentions that she's allergic to dairy, which was revealed in "Candace Loses Her Head".