i'm not sure if you're still confused with this but here's a better explaination i think.
Huf, the store, has accounts with nike, converse, vans. They are sold at both SF and LA locations. Given that, Huf the store, is entitled to co brand any shoe company in which the store sells. Why can this be done was your question? Well its simple. As soon as the Huf logo, etc was trademarked. As soon as the first store opened, Keith separted himself with the store as being a complete different entity. So the store and The Huf name are totally seperate from Keith Hufnagel the rider. Just as he has done Huf store collabs with DVS, he is also completely free to do store related co-branding for any company he so chooses. Now, if Keith Hufnagel himself endorses a product, than all the companies he rides for are all he has to pick since he is under contract with these companies under "Kieth Hufnagel." this makes Huf, and everything product related, something that is totally different.
is that a bit easier to understand?