Already Applied Once Several Years Ago, Applying Again - Please Help

Hello all! I am looking for any and all suggestions or information that could be useful for my second round of applications and realistic expectations for acceptance. I am going to try to keep my biographic info short and to the point, but provide the necessary components. I’m really looking for info regarding where I’m lacking on my application and ways I can improve going forward.

Undergraduate (2013-2017): 3.63 in Biochemistry and Molecular Biology, minor in Business Administration, Collegiate Athlete (Cheerleading), Undergraduate Researcher for one semester, shadowed at an orthopedic clinic for a semester (90 hours), volunteered in numerous organizations, and tons of leadership positions on campus including sorority Director of Alumane Relations, various committees, etc. Took the MCAT twice, making a 498 and then a 503. Applied in that cycle my senior year to 6 schools, with 5 being out of state.

I moved to the state I’d ultimately like to go to medical school at and earned residency there. Wasn’t 100% convinced I was ready for medical school at the time and looked into ways to be in healthcare maybe from a business or administrative way.

Graduate (2017-2018): 4.00 in Master’s in Business Administration at the school I would like to attend. Worked 2 part-time jobs to pay my bills during this time. Continued to volunteer, but did not shadow very much.

I just graduated with my Master’s in August and am planning to apply in 2019 for class beginning in 2020. I currently work at a staffing company and love being able to help people find careers, but miss the clinical environment. I have tentatively scheduled the MCAT for a date in April and am studying now, as the schools I am applying to will not accept my prior scores and I would like to do better as well.

Based on this info, I have a few questions. Also,I would love any and all feedback you can provide.

I am planning to shadow more soon, but how many hours should I aim for? I have a total of 105 hours currently, but they date back to undergraduate and I would like to show a continued interest.

I am planning to take many more practice tests for the MCAT this time and truly believe I can score better than my last two tests. How much will my old scores affect me, as they aren’t as strong as the school typically accepts? Will progress and diligence look positive to the committee?

In terms of letters of recommendation, I am planning to get letters from my undergraduate advisor (a science professor) and 1-2 of my other science professors (including the one I researched under). I don’t have any way to earn more recent science letters, so should these be acceptable?

I’m also planning to ask for recommendation letters from 1 professor from my MBA program and my current employer. For my last application, I also asked the doctor I shadowed for a letter, as I have developed a very strong relationship with him. Would these be good? Any thoughts?

Also, will being a second-time applicant prove to be helpful for my application? I’m trying to be realistic about my chances of acceptance. Thanks in advance for any and all suggestions or answers! They are greatly appreciated.