Your best bet is just take the boots in with you so you can make sure they fit.
This guy speaks the truth... In general all the brands are going to fit your boots, it's just a matter of getting the bindings with the straps you like, the right amount of flex, and then find the model that fits the best.
If you plan on keeping the board/bindings through a growth spurt it might be worth erring on the side of slightly bigger bindings. That way you could stretch your gear out for a few years.