No, but there is no one size fits all answer to your question. You know your study habits better than anyone posting here. Do you think you need 3 years to prepare for a 7/8 hour test? If yes, than by all means go ahead and start. See
https://www.aamc.org/students/applying/mcat/mcat2015/faqs/
If med schools don’t require it, why do you think you need it? Keep in mind material in premed courses is not so much meant to carry over to med school, but to give adcoms a way to compare students taking same somewhat difficult science courses. Again, however, you know yourself better than anyone here. So if you believe you need the security blanket of college anatomy and physiology then go ahead and take it and make sure you do well in it.
Typically med students are exposed to basic science first two years and then are given one-two months to prep for Step 1. If you believe think you can learn this stuff from flashcards without a framework that med school would provide, good luck. Here’s a link to sample step 1 questions.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCkQFjAA&url=http://www.usmle.org/pdfs/step-1/2014samples_step1.pdf&ei=f5nqU72iFYigogTvkYLoBg&usg=AFQjCNFmji6F37MxuKyCS5RF_DC6qZVGTw&bvm=bv.72938740,d.cGE
you are right you need solid overall app. Nothing is guaranteed, not even a 45. As interviewing is a learned skilled maybe consider acquiring, reviewing interview prep materials and as actually practicing interviewing as well.
with exception of bio, maybe calc, although colleges may give you credit for AP courses, med schools tend to require completion of physics/chem at college level. And if med school accepts AP bio credit then you'll have to take upper division bio courses which shouldn’t be problem as molecular bio major if you do well in them. Talk to advisor.
besides major and premed related, take any course that interests you and that you can do well in
As I am resident, I agree fully with drcrispmd (an attending physician) posts above, you should not be giving any thought to USMLEs. It’s truly pointless.
as to med tech course, only if you find it interesting and can do well in
It’s really good to ask questions. A college prof once told my class “please ask me questions, it shows me how stupid you are.” You may not like prof’s phrasing, but it gets to point of why we ask questions, to learn something we didn’t know. A flip side however is sometimes when you ask a question, you get an answer you don’t like or is annoying. Learn to move on from on questions you don't like. Fighting back tends to rain down more negativity.