This is an example of direct Mexican parroting of the English word "rifle". However, be careful with this slang cognate......it is pronounced "REE-flay".
A constellation of sixties hippie expressions which are still quite current. This is the standardhip youth greeting, as ubiquitous as "What's happening?"
The word means "eggs," but the reference to "balls" is so strong that you have to watch out using the word at all. Polite girls would probably order blanquillos (little white things) from a male waiter.
Mi'ijo is a contraction of Mi hijo--"my son"--is like "sonny" used in addressing younger boys. Affectionate use of mijo between friends and peers is a major Mexicanism. Mija (MEE hah) is used to address women, the same as mijo with males.