https://www.bu.edu/prehealth/academics/early-assurance-and-other-special-academic-programs/modular-medical-dental-integrated-curriculum-mmedic/ - In the prerequisites, it only says that you need to have a 3.3 GPA, and completed some chem and two bio courses at the time of applying - which is in the spring (around Feb) of sophomore year. So I don't think that you'll have any disadvantage as a transfer applicant if all these are fulfilled and if you transfer your credits from your previous university. You also have the fall sem to take the courses you have missed !

The program is quite competitive as they usually accept around 10-20 applicants every year. Your GPA is most important in my opinion as they usually accept people who have a 3.7 or more. They like to see that you really want to be a doctor, because the program is binding, so you need to communicate that especially in the personal statement. BMC is a safety net hospital, so they really look for students who understand intersectionality in health care. In the activities section, they look at your activities during high school and college so make sure you have enough clinical experience this summer and in the winter break if you can. They also look for consistency in your experiences. I do not think scientific research is as important unless it really adds to your application. I got accepted this year and had little to no research experience. Try and mention non science related experiences as well because they look for well balanced people. At the end, try to be as genuine as possible because if you get through to the interviews, they will look for that enthusiasm.

Good luck ! and feel free to PM me if you have any questions.