Trust me, it won't come in the near future. Unfortunately, the snapchat devs aren't interested in creating a windows phone app as they feel we are insignificant. Though 6 snap is a good client app, better than the actual IOS snapchat app.
Rudy offered 6snap for free to Snapchat to convert it into the official app. But even then they haven't done anything. They're just Microsoft haters like the Pebble CEO.
not really with Snapchat's kind of picture, captions, etc. (CyberDust works almost perfectly actually, but I wish it had a screenshot ability, since my SO and I are kinda sentimental)
I only really use Snapchat with one person, so it isn't bad, but try getting all your peers off of Snapchat, nope.
I'd go for MS's WindUp, but it'd have to be on iOS I guess.