NBGI never needs an excuse to do what they want XD
I don't know if I'm missing something, but what difference would it make if they wear it in a Vs. Jupiter stage than any other stage?
and yeah, while you're at it...
The first four (main) accessories are the "Vampire Mouthpiece", "Heart of Vampire", "Bloody Nails", and "Flying Bats".
The second four (ripoff?) accessories are the "Gothic Headdress", "Gothic Rose Corsage"(?), "Gothic Frill Brace(let)", and "Gothic Frill Ankle(t)".
Not that anyone needed to know the accessories, but hey.
Wiki ahoy.
Hey, I wanted to update the compendium eventually to reflect either romanji or translated in the file name, and if I ever get around to it, I wanted to display it with the program I wanted written up, so don't think the efforts are getting wasted.
Besides, there's people who'll always throw names and descriptions and other stuff at me which I won't always guess right, and stuff. The more I got to draw upon in my crystal balling efforts, the better. I mean it beats "Black frilly bracelet" or something.

And Corsage is correct... as much as I hate wearing them myself. *shudder*
I also did a point count...
According to im@s2's DLC page at -
http://www.bandainamcogames.co.jp/cs/list/idolmaster/im2/dlc/According to my calculations to complete Catalog 4 (To successfully get the bonus costume), you will need:
1x1000 extend -1000 so far
3x500 (1 starry, Luxury and Floral) - 2500 running
1x1200 song - 3700 running
4x200 assessories - 4500 running
4x300 accessories (Requires top 10 chart achievement) 5700
1x0 head accessory (only if you bought the rest above)
... I HAD 6000 MS points stored up.
*cry*
I think the hamster getting updated is going to be a catalog 5 or 6 thing. *sigh*
Would it be against the rules to request a donation run to get 1500 MS points so I can get that STUPID Hamster?

(edit - Can't count. There's 9 cell numbers you need to get and 300 points nets you 1.5 of them)
Edit 2 - TweenDoriru provided a correction - Apparently the requirement for these costumes isn't quite so severe.