Well... First of all if the two of you do this I will love you both forever. Second of all: The tail may just be the easiest part of the whole thing. Large styrofoam balls covered in paperclay and then sanded and painted! All you would have to do to attach them together would be to run a wire through all of them so that they make a tail. The barb on the end you could sculpt from paperclay while covering the styrofoam, what since paperclay air-dries.
Her kimono-thing and her corset would be the harder parts. I myself would make the corset out of leather and put all sorts of boning in it, but that might be too hard for a beginner... Why not try just regular black cloth for that?
Now I'm not much for advising on patterns, but I would have to say that her kimono-thing would be pretty easy to just BS if push came to shove. Doing something like modifying a robe pattern to give it large bell sleeves and a neck like that wouldn't be too terribly hard. But then again, I just put stuff on a dressform and hack at it with scissors until it looks right. So please don't mind me ^_^;
Viral would be rather interesting. For his armor I would suggest the craft foam method, and a pair of big honkin' plastic werewolf hands for his mole hands.
Maybe you should try asking in the TTGL thread on cosplay.com?
http://www.cosplay.com/showthread.php?t=116088Everyone there is very nice, they'll be able to help you!