I didn't read the first part of the OP's paragraph. In regard to specific schools, I can't say that I actually researched this much because I already had completed several degrees before I even took the MCAT myself. I would start by looking at an MSAR.
I think that it depends on the overall style of the school. Freeze's med school is very traditional--they still use A-B-C grades, weigh MCAT scores heavily during admissions, and they will take you as a teenager as long as you meet the standards and prereq's regardless of whether or not you have an earned bachelor's degree.
The med school in the Sunflower State to the north admits under very similar standards, GPA's, and MCAT averages, but they use the more modern grading system. While they admit you while you are still in school, they require a bachelor's on your transcript prior to matriculation. By require, I mean that they will literally tear up your admissions letter in your face if you didn't finish your degree in the time between acceptance and matriculation. It could be a degree in general studies, but a degree is required nonetheless.
Travel to the south, and the two big dogs in the Lone Star State are opposites. UT-Southwestern is an A-B-C school that doesn't require a bachelor's. Baylor is honors/pass/fail but advertises that all of their matriculants have completed a bachelor's. Note that both have similar admissions profiles--it just depends on what each individual adcom values.
Carlos, I'll tell you what I tell everybody else. You could have 20 years of nursing experience, worked with the peace corps every summer since 1990, a Ph.D. in a biomedical science, and be the ancestor of multiple generations of physicians (the latter of which would probably be the most valuable). If you don't have the numbers, your chances will be very limited. So study and nail that MCAT. That will be your ace in the hole because it is the only way that schools can compare students of such varied backgrounds. Also note that "average MCAT" is a relative term. My score was well above average compared to my current classmates, but it would be considerably below average if my school was a top quintile facility.
Look at the websites of schools that you are interested in. They are usually very forthcoming with what they expect and what they require.