The control pad on Kim's Kimmunicator turns blue for a brief moment while asking Wade for a ride.
The remote control for the hovercraft disappears from Du's mouth after the rope comes down to rescue them.
I fail to see this as an error. Since Du had to use his mouth to grip the rope, obviously he had to do something with the RCM, whether it be to spit it out or take it fully into his mouth. Just because we do not see what he did does not make it an error.
When Ron says "Killigan's Island", it is an allusion to the old show Gilligan's Island.