1. Why do you do what you do?
2. To make money?
3. That's quite pathetic. What a waste of life! You are not immortal, remember?
4. Would you buy from a firm that's only in it for the money?
5. Don't be a firm you yourself won't buy from.
You can't come up with a mission. Coming up implies you don't have one. You can only recognize/discover it.
Core Values -
I don't agree with the literature here. Be driven by the right values, not by some arbitrarily decided core values. Values are abstract anyway. Don't offend them by binding them into words. Don't worry about getting 3-4 abstract words. You can use them for marketing stunts though. See my linkedin for reference.
Once again, you can't come up with it. It must occur to you. When you quit doing dumb things and get your shit together, it will start to occur to you. Allow yourself to experience your vision. The more you trim away dumb things from your life, the clearer your vision will become.
This is the only controllable part. Once you have gotten your head straight, what can do about the vision that has revealed itself from amidst clouds of uncertainty? This is your BHAG. I say do the highest you are capable of. Go a bit beyond. Reach a bit higher.
For strategy consultation, reach me at email@philosophicallyinclined. I don't do this for free. If you want free shit, read my blog. Try this post.