3) Is "Head First Servelets and JSP" book which was designed for the 1.4 test good enough to pass the new test?
It covers almost all the objectives, as outlined in the previous answer. However, whether it's good enough for you is a purely subjective question: the answer can only be based on your own expertise, learning style and confidence. You will need to base your choice of books on what helps you learn most effectively, and only you can make that decision. Members of this forum can provide recommendations based on personal experience, but we cannot tell you what to do. I would advice checking SCWCD Links and researching the available resources (books, mock exams, free notes and tutorials).
Charles Lyons (SCJP 1.4, April 2003; SCJP 5, Dec 2006; SCWCD 1.4b, April 2004)
Author of OCEJWCD Study Companion for Oracle Exam 1Z0-899 (ISBN 0955160340 / AmazonAmazon UK )