Welcome, I'm sure somebody here will weigh in with more in depth info, but to answer your questions:
1. There is no official word. Some reports say he's working on it, some say he's planning to work on it, some say he's not going to publish another book about Welles.
2. A former newbie asked the same question and memeber Tony gave a more than complete answer. Check out the link:
If it doesn't work, the thread was titled "questions from a newbie" from early February ('03).
3. Sadly someone here emailed Criterion earlier this year with that question and the answer was that there are no plans for it in Criterion's future.