I'll tackle your second question. There are two types of recruited athletes -- "blue chip" and others. Regardless, all go through the exact same admissions process. You fill out the same application, take the CFA, have your medical exam, do a BGO interview (other than recruits for basketball and football), etc.
You are absolutely NOT guaranteed of an appointment. I've had many recruited athletes who receive turndowns. And, some drop out along the way -- both for academic and medical reasons.
Blue chip athletes (those whom the coach really, really wants) might have slightly better odds of an appointment. However, there are lots of great athletes who want to attend USNA and each coach has limited numbers of blue chips each year (not sure there is a fixed number but it clearly depends on the sport and the size of the team).
As for your first question, I'll let a more recent mid answer other than to say that, yes, you still go through Plebe Summer just like everyone else and, with some exceptions (i.e., team tables), your time at USNA is largely the same as a non varsity athlete. However, b/c of the time commitment of a varsity sport, you have to be even more organized and disciplined to get your work done and to do well academically.