1. The standard vesting arrangement is four years with a one-year cliff. This means 25% of your stock (as a founder) vests at the end of the first year, and the remainder vests month-to-month for the next three. In your scenario it sounds like the founders have been at it for two years before their first financing.

2. Why does the VC even have the right to fire the founders or CEO? The board has that right, and presumably the VC is on that board, but their rights are defined in the financing agreement. Control is an important negotiating point when raising a round of financing.

3. Why would a VC want to invest in a company where the founders have completely vested? What's to stop them from running off with the money, so to speak?

4. That said, I've seen incorporation documents where some small portion of the founders' stock is vested immediately (maybe 5%), and the remainder follows the standard four-year vesting, one-year cliff arrangement. This makes it a little harder to raise money and the VCs might insist on changing the vesting schedule as part of the financing agreement. Generally it's just easier to have everyone on the same vesting schedule, that way nobody can object.