My kids (6-8 boy and girl) have had pretty good luck with the Kamik Rocket boots. They’re a lined pac boot and if you read reviews, the fit is either perfect or tight. The pac liners aren’t a universal cut and tend to be a bit narrow at the toe but they fit my kids perfect. They have “average” not-wide feet. Baffin is also a brand we have good luck with. There’s always Bogs and Mucks. Not sure what your budget is. Also, consider a thermal sock liner and/or wool socks if the pacs (of any brand) are too tight. Cotton socks are foot freezer for sure. Leave some room for air circulation and you should be good to go.
This may sound strange but have her a wear a scarf or a neck gaitor. Keep the the kidney area warm too. You’d be surprised how well the body can regulate its own heat when a few key areas are kept warm. That is also the key to keeping other extremities warm. Keeping your core warm. And a good hat.