Search:

Unfortunately, costume hangers weren't the worst prizes. Majority seemed to get Extreme Core (Lv. 7), Superior Core (Highest) and the Caps. Oh well, that's lottery for you; at least you're guaranteed...

It's not being offered in the level up event; the only thing pet related is the Pet Slot Extender. IIRC the last time they offered these kits (directly) in the cash shop was in May. However, they...

You select what you want untrained.

https://www.youtube.com/watch?v=O6visnfyMSQ