I have (naively) not considered programs other than Statistics, so that is a helpful comment.
Just making sure I understand the part on finishing in 4 years since I am still learning; PhD sequence is roughly (1) Take Masters Courses (2) Pass qualifying exams (3) Enter Candidacy - Research/ take PhD courses (4) Comprehensive Exams (5) Thesis defense. Your saying that with adequate preparation I can validate (1), (2) thus reducing the entire length of the program (like your friend did)? My guess is that this is program specific but speaking generally probably best to load up on electives that prepare me for the qualifying exam(s) (Applied Stats, Stat Theory, complimentary math classes - real analysis, linear algebra, etc.)?