I'm an upcoming first year, I don't check this often but will try to answer any questions you guys have.
From what I have heard the secondary questions do not change much from year to year. I would look at last years thread to get a good idea. I do know of people getting secondaries but their system was down for an extended period. That being said, I would assume now that it is back up, deadlines will not change.
For the ED people asking questions about deadlines, this was taken directly from their website:
https://medicine.mercer.edu/admissions/md/information/committee/
Early Decision Program
August 1, 2018: Primary AMCAS Application & Transcripts must be submitted to AMCAS.
August 24, 2018: MUSM Admissions Office must receive an applicant’s CASPer score and GPA and official MCAT score(s) on a Verified Primary AMCAS application by 5:00PM ET for a Secondary Application Invitation for the Early Decision Program to be considered.
August 31, 2018: All Secondary Application components must be submitted by 5:00PM EST.
Early Decision Interview Information
August 23, 2018: Interviews start
September 5, 2018: If invited to interview, applicants will receive an email invitation no later than this date.
September 11, 2018: Interviews End
Also, as a word of advice, prior to filling out the secondary and or interview day (especially ED applicants) be sure to read up as much on MUSM as possible. Go through their website, know their mission statement, know how you can help support this mission statement, and also check their social media outlets (FB, youtube, etc.). Essentially, you want to have as much information as possible prior to starting this process.
On a final note, good luck everyone!