User blog comment:Jkphantom9/Volume 3 Episode 5 Preview/@comment-5426254-20151204014938/@comment-4010415-20151204035155

No, the guardian is Zwei.

Also, I think Nyan Cat is intentionally trying to piss Yang off. They might be trying to get Yang and Weiss to slip up in their anger.

I think the change in plans is due to her gaining access to Ironwood's system. It seems she didn't expect to actually get Ironwood's Scroll as an access point, and it's just too good to pass up.