(copying from comments)
There are way too many possible scenarios to consider. For example, you say "what happens when CEO gets replaced?" What normally happens is the employees report to the new CEO, and business resumes. But clearly, that is not your question. We cannot tell what other scenarios would occur and how employees would deal with that, so you could narrow it down to a specific scenario. Your question #2 also complicates matters. As pointed in the comments, we prefer one question per post here.
Leaving that aside, #2 by itself has too many possibilities. An employee is expected to keep his boss in the loop on everything that he works on, but on the one extreme this becomes micromanagement, and on the other, the manager is completely clueless what his team is doing. Most teams manage to pick a point somewhere between the extremes, so in your case, the employee, the CEO and the director or whoever will decide how frequently the CEO should be updated. There are way too many possibilities, which you should narrow down.