What exactly does the "Jobs unlocked" drop box do? I figure the box next to it means job level but I'm not sure exactly what that dropbox means.
It means what jobs they've unlocked ... not sure how you get confused on that.

Base is the unlocking of the base job. If the person is a Holy Knight, their base is Holy Knight. If they're a generic, then their base is always Squire...
If you set it as Mime, then they've not only unlocked Mime, but all the classes in order to normally unlock Mime. For example, if you set it to Wizard, then they have Wizard unlocked and 2 levels of chemist.
well i was more confused along the lines of why i can only choose one class as the unlocked class but that makes more sense. So if i have somenoes job as Knight but set their jobs unlocked to squire will that cause complications?
It might ... then again, they just may not have any knight skills what so ever in that case.
lol i guess i'll test it whenever i get some time.