ASk HN: 2 questions about founder's equity

When it comes to founder's equity, the general rule of thumb seems to be to vest it over 4 years and have a 1 year cliff (so if one of the founders leave before a year is up, they lose their equity. So far so good, but here are my questions:

1. What if one of the founders isn't doing much work during the first year and they refuse to leave on their own accord?

2. After the first year, what if one of the founders decides to start another company on the side without his partners? Should that company be considered part of the original startup?