On the way to Franken Castle Freddy is wearing his standard white shirt with blue collar. But when the gang pull up to the Gypsy wagon and Freddy says it would be fun to go inside, he can plainly be seen wearing an all white shirt with his orange ascot, no blue collar. Inside the Gypsy wagon Freddy is then wearing a long sleeve white t-shirt with a blue scarf, his upper back is clearly exposed. In the next scene he is back in his usual attire.
When the gang arrives to visit the castle, they start to cross the drawbridge. The vampire appears and warns them away, then the drawbridge starts to close, trapping Daphne inside. If the vampire had simply closed the drawbridge before the kids arrived, they likely wouldn't have gone in the castle in the first place.