College credits or AP courses as a HS?

[premedengineer]

I started accumulating college credits at a community college last year, when I was a junior. Now, this year I will be going full time and hope to transfer out 50+ credits at the end of the year to a 4-year university of college. My questions: Is it more beneficial to transfer in college credits or AP. Also, will I have to take a placement exam for these classes? Will colleges consider me a transfer student instead of an incoming freshman and make me ineligible for freshman scholarships? I want to attend either U of M, Mich Tech, Hope, Calvin, Wayne State University, Kettering University, or Lawrence Tech (and I think I'm leaning towards U of M). Oh, and I want to attain a degree in engineering (mechanical or bio) while fulfilling my pre-reqs for pre-med. I don't have a preference as to which pre-med program I attend but I do for where I go for engineering. Can anybody recommend a good school either those listed previously or some other one? I have extensive extracurricular activities, 30 ACT, 3.7+ HS GPA, 3.9+ College GPA, and have published a scientific paper while an intern at a well-known worldwide company, but no shadowing (however this last year I hope to attain 50+ hrs shadowing my friends doctor).