Here is how anyone can be an "Illuminati".
1st, remember that like "Anonymous", there is no membership, only recognition of your actions. If you want to be "Anonymous", then you are "Anonymous".
If you want to be "Illuminati" (an enlightened one), there is no membership, only recognition of your actions. If you want to be "Illuminati", then you are "Illuminati". Like "Anonymous", it's just a word.
What actions make you an "Illuminati"? You have to recognize that people en masse are stupid (deluded). They easily fall pray to things like get rich quick schemes, conspirosy theories, super-natural events, etc. "Illuminists" know this and can use this information to bend people to thier will (e.g. propaganda). It works. If you make your living off the delusions of others (e.g. politics, religion, etc.), then consider yourself "Illuminati".
With your new "Illuminati" know-how, start a Fraternity (College Allumni Frat, Business Frat, etc.). You now have a good ol boys network of "Illuminati" who work together.
Now that you have an "Illuminati" group, it will make for a good piece of Gossip/Conspiracy Theory/ that "Non-Illuminati" can use to blame all thier problems on.
There is a reason why the authors that you quote (e.g. Maars), is in the section its in at the book store.
Also, remember that signs and symbols are just that...signs and symbols...brands. They are hashed and rehashed over and over again by different people and groups over many years.
Of course, all of this is just my opinion, and as such is open to suspect and scrutiny...which I always welcome.