Clothing design for quadrupeds:
Doing it wrong. While the leg-enveloping dress design is fine for vertical bipeds like humans, any quadruped in an outfit like this is likely to end up stepping or tripping on the dress. This is not a problem for the short skirt, but it still looks ridiculous and uncomfortable for the quadruped. It is not designed with the horizontal body plan in mind.
Doing it right. The "skirt" half of the dress only covers the dorsal part of the animal - less like a human skirt, more like a peacock's train. Unlike the first two dresses, these dresses takes into consideration the body plan of the individual. Even a formal dress with a long train designed in this manner would allow proper horizontal locomotion.