I liked the Ed Sheeran scene, minus Ed Sheeran.
It's purpose was to make Arya feel uncomfortable, and possible change her direction from Kings Landing to the North with all the talk of family
My problem with the Ed Sheeran scene was how they do the thing where they have a cameo so they linger on their shots. It was lowkey enough otherwise to not really see it as a big deal.
I see the scene as the first crack into Arya's warpath. It happened a bit earlier than I expected, but she's been so fixated on killing people, and seeing them as targets, that a bunch of bros being nice could begin to make her reconsider. It's also quite a change of pace to see a scene in GoT at this point where people welcome a stranger, share their food, and nothing bad happens.
I think the uncomfortable thing is because besides the possible immediate danger, these guys are humanizing their own families. Arya had just killed off the Freys indiscriminately.
Where that leads, I could see it ending up like you said, Cat Bowser.
It's notable that the corpses the Hound and his gang found were the father and daughter who fed and gave shelter to the Hound and Arya way back in season 4. The Hound ended up stealing the guy's silver and figured he and his daughter wouldn't survive the winter.
