User blog comment:Seishoujo/Next time there's a Q and A sessions.../@comment-24088073-20131109084214/@comment-4010415-20131109183350

Where did Monty say that Ren has Jade Dragons and Sun has Gunchaku. Those are fan-given names for the weapons.

Also, Monty's response on the subject of Ruby and Yang's relationship on why they're sisters with different last names is that we'll find out when the show itself reveals it.

https://twitter.com/montyoum/status/398475565952299008 "you'll find out in the show!"