I am in a similar situation as you. I am thinking first of all go with what you know is generally required by all medical schools (most), 2 science and 1 non science which takes care of #2,5 and 6. The others in my opinion is where you have flexibility. You definitely need the MD letter because I feel that adds a lot to your application ( someone doing what you want to do is telling adcoms that you can do it, the number of years you have known this person is also a big factor). between the tutor coordinator and the lab research professor, I would go with the latter. Unless you have been out of school for a while and tutoring is something you did during that time. If not, I think that the activities section should be enough to get that across ( i think the fact you have been there for 3.5 years speaks for itself). The research LOR gives the balance to your application and contrasts the MD recommendation, making you a very balanced applicant. This is just my opinion, I am in the same predicament so i wish you the best of luck!🙂
edit; I missed the PI for research part in that case, i think the tutoring recommendation should be the better choice.
