Military guy here with no commercial background—is this to say that pilots currently working for Brown get “first crack” at vacancies which pop up due to retirements and attrition (i.e., a system bid), and once that re-shuffling has been awarded, the newly-vacated spots downstream are now offered to new hires?

If I understand that correctly, it begs the question of when the next vacancy bid (or system bid—not sure which term is more correct) is set to occur.

Did I get all that right?