
Yes, that's why they are dressed up in robes from different houses (green for Slytherin, Maroon for Gryffindor, gold for Hufflepuff, and blue for Ravenclaw...), they are supposed to be helping you "sneak out" of the castle...
And I agree, but IMHO, a lot of creatures from OUR proposal would be cut out xD... All they would need would be quite a few recognizable creatures, such the hipogriff, unicorn (in the books, there was one time when the students got to see baby unicorns as adults were so hard to come by. The baby's were all different bright colors, because they didn't turn white until adult hood. Something like this could work out similar to the "Triceratops Encounter"), Aragog, and a Blast Ended Screwt (those things could be great for funny special effects xD)...