I ranked each cast on placement and on the average amount of confessionals each contestant received per episode, that way I got one list to represent presence and another to represent longevity. I then took each HGs average rating across both lists, punched all the ratings into a normal distribution chart, and based on who is in the top tier, that gave me the "main characters" of each season. I included their average ranking across both lists.
BB2: Will Kirby (1/12) & Nicole Nilson-Schaffrich (2/12)
BB3: Danielle Reyes (1.5/12) & Lisa Donahue (3/12)
BB4: Alison Irwin (1.5/12), Jun Song (2/12), & Robert Roman (3.5/12)
BB5: Diane Henry (3/14), Drew Daniel (3.5/14), & Marvin Latimer (4/14)