To start with, the CEO leads by example and what he genuinely believes in and practiced is followed by the rest of the team. That is why the vision has to be framed on the basis of the CEOs beliefs.
Remember, the vision is a short, future focused, statement - a vivid picture of where the organization is headed in the very far future.
Example: Caterpiller's Vision "Be the global leader in customer value"
On the other hand, a mission is focused on the present and describes the business of the organization.
You first need to decide on your core values - then create the vision. Culture develops based on what you habitually do but it is good to defined what kind of culture you will follow. Mission comes later.
If you want to discuss this connect with me on firstname.lastname@example.org