The burning of winterfell confused me aswell, but I just assumed this was something to be explained later. They never showed anything about the people doing the siege, so it looked to me like they did it after taking over/back winterfell, for whatever reason to be explained later.

Quote Originally Posted by wufwugy View Post
Arya is probably the most well-off Stark ATM
I would say so, she has the ultimate trump card to turn the tide for her lineage, the God of Death is in her pocket.