Alright, I just built it yesterday.
Yes, those are cat ears. Definitely the most hilarious portion of the design. It's essentially a female version of the 00 Qan [T].
As for the weight of the weapons binder, it's not horrible. I have noticed that in some poses it will begin to add weight to one side of the kit, but as long as you're careful with how you pose it you should be fine. If you have an action base, however, it doesn't matter at all.