Hi Deena,
Obtaining the documents you listed will help.
The birth act is his Italian birth certificate. In general Italian vital records contain more information than our older USA records. Women never loose their maiden names in legal records.
I would suggest reading Tafford Cole's book, Italian Genealogical Records. You should find it at a library. I use it so much, I bought a copy. In my opinion, if you are going to do serious Italian research I think that book is one of the must reads. It certainly became my "bible" for Italian genealogy. Lynn Nelson also has a book "Discovering Your Italian Ancestors" that is a good source. These books explain the various records, give examples of the actual records and translations.
I suggest starting with John's birth record as it will contain the names of his parents , their ages, and their place of birth.
I was just curious about how the public trees on Ancestry worked. I have always wondered if once you made your tree public, you could then remove it. I have not "published" any of my work on the internet. I think it is a personal decision. It can be a great way for lost cousins to find you.
Another source of information is USICS. A request may take weeks (some have reported several months) to receive a reply, but it is free. Request a copy of the entire record. Send one for each of your great grandparents.
http://www.ice.gov/about/legal.htm#foia
Debbie