For finding quick meanings of symbols and abbreviations I think Google is a good source. There's a wealth of information available online. Mackey's
Encyclopedia of Freemasony is pretty good. Also,
Sacred Texts has a list of e-books on Masonry as does the
Hermetics Resource Site. The standard meanings of the symbols are just the beginning though; they're a jumping off point. It's up to each person to develop their own meanings through meditation.
As far as the books you mentioned, I wouldn't really recommend
A New Encyclopaedia of Freemasony. It's a pretty good reference work on Masonry, but I haven't found it that helpful as a companion for the Masonic Tarot. It does give meanings for some of the abbreviations but I don't think it has any that can't easily be found online. I don't know anything about the other two books.
There's one book I've been hearing a lot about lately though I've never read it,
A Bridge to Light by Rex R. Hutchens. I've heard it's quickly replacing Pike's
Morals and Dogma as the text given to Entered Apprentices upon joining a Lodge. Hopefully someone's read it and will be able to comment.
One hardcopy book I have and refer to quite a bit is
A Dictionary of Freemasonry by Robert Macoy. One to watch out for is
Lexicon of Freemasonry by Mackey. It's just a condensed version of his
Encyclopedia which is availalbe free online.
A Brief History of Secret Societies by David V. Barrett is one I'd recommend. A good chunk of it is devoted to Freemasonry. It's a good overview and should give you some insight into Masonic history and practices.
Here's a link to a website that gives an excellent summary of what the Scottish Rite is all about.
http://www.aasrvalleyofjax.org/scottish_rite_degrees.htm