It was top five wolves in North America - not just alphas, but overall, because if I remember right, Sam and Charles were both on the list and neither is Alpha; but Adam was right behind them, and he's not in Bran's Pack, although he is one of Bran's wolves - one of his Alphas. Does that make sense?
When I think of the power structure of the werewolves in north america I use a feudal template to keep track.
In a feudal kingdom you have the King and his heirs ruling the premier and most powerful area, call them Duchies. The King controls the most powerful duchy. So the heir to the most powerful duchy should inherit control of that duchy as well as control of the kingdom as a whole. But remember the most powerful duchy is still a duchy among duchies. If one of the dukes over throws the current order of things then his duchy becomes the most powerful and he's now king.
Which is my way of saying, the ranking order for the most powerful were's in North Americas Were Kingdom are: King Bran followed Princes Charles and Samuel, followed by Duke Adam and Duke etc, etc, etc.
Not a perfect fit, but if you know about how feudal kingdom's work it gives you a decent template to keep track of things.
Also with Bran. I tend to think of his as basically having two packs. The first is his Aspen Creek Pack with all the normal werewolves, Second is his North American Alpha Pack. He can in theory draw upon the power of both his regular pack and every alpha in north america. But I think that as has been shown with the mate bond versus the pack bond, Pack Magic has different types of magic bonds available between were-wolves, so I'm unsure if the bond the Marrok has with his pack are different from the the bond he has with his Alpha's.
The Deposed King