I understand why people jump to the conclusion that its Rick and Mike, or Gavin... but there isn't just skateboarders running these things.
The undesirable partners are most likely outside investors who want to see continual grown of their investment (company).
When the board meetings took place it sounds like Koston, being part owner of Lakai at the time, has ideas of his own and the other people in the room decided to continue the path they were on.
Obviously, being a company owner, Koston wanted some say in how the company is ran and its direction. Once he saw that his word in the company didn't carry, he was over it and decided it would be better "work" for a company (Nike) and be taken care of, then battling outside investors opinions on what is right for the company.
Now, the saltiness with Rick and Mike most likely is coming from them being trapped with Lakai and having to work around the investors they put into place. Im guessing they were saying "oh shit this isn't how we planned, but now were already neck deep". I'm sure Rick and Mike want to keep their company going and make money, but they have to essentially fuck over their friends by listening to the investors.