Mars’ Closest Approach is on 10/6
Mars’ Greatest Brilliancy is on 10/12
Mars’ Opposition is on 10/14
I can’t picture in my mind why they don’t all happen at the same time.
Mars has a more eccentric orbit than Earth. Rather than flying in parallel imagine Mars on a diagonal path relative to Earth's orbit. The greatest brilliancy is based on a combination of Sun-to-Mars and Mars-to-Earth distance. Since Mars is moving away from the sun now, I would have expected greatest brilliancy to be just before the closest approach.
If the closest approach is today, does that mean Mars is close enough for us to see the flag left there by our astronauts?