Awesome update and I thank you for it.
I'd also like to suggest one thing. As far as i have been informed at the moment, you will not be able to open skeleton boxes and get anything let alone the pet after the event ends.
My suggestion is: Make skeleton boxes act as Christmas crackers in Rune scape 3 - let the boxes be discontinued aswell and keep the ability to get rewards including the pet from the boxes after the event ends.
Thank you.