edit: JAXA’s Mercury Magnetospheric Orbiter (MMO) is now called MIO – Mercury Magnetospheric Orbiter’s New Name.
With all the fanfare about BepiColombo (mine included) I didn't realize that there were two spacecraft on this launch. From Spaceflight Now's Ariane 5 launches two satellites on 7-year voyage to Mercury:
The climb to space went smoothly and 27 minutes after liftoff, ESA’s Mercury Planetary Orbiter and JAXA’s Mercury Magnetospheric Orbiter, both attached to an ESA-supplied carrier spacecraft known as the Mercury Transfer Module, were released from the Ariane 5’s upper stage to fly on their own.
@DavidHammen's answer explains that the "final approach" to stable orbit around Mercury from an is complicated and will be in the neighborhood of Mercury for a short while to do so.
Question: At what point will the two spacecraft separate? And once separated, will they have similar orbits, or move to different orbits because of their different science objectives?