Vulture have revealed that auditions are underway for four new characters, including:

Michael Perkins (Mo McRae), a “new second-grade teacher at Otter Bay Elementary School”, accidentally causes Amabella to have a panic attack when he lectures his students on global warming. Unsurprisingly, this doesn’t go down well with Renata (Dern) at all.
Corey Brockfield (Douglas Smith), who is described as an off-beat surfer, aspiring marine biologist” and employee in the school administration office. it isn’t long before he finds himself bonding with Jane (Woodley) over their “deepest secrets”.
Elizabeth and Martin Howard, aka the parents of Bonnie (Kravitz), are also set to rush to Monterey when they learn of a “family emergency”. As we gathered from Bonnie’s scenes in the first series, there’s more to these two than meets the eye: Elizabeth is said to be “controlling and abusive”, while Martin is “emotionally distant”. And it is worth remembering that, in Moriarty’s novel, Bonnie ends up saving Celeste by pushing Perry to his death. Bonnie later reveals that she grew up in a similarly abusive household after witnessing her father’s violence toward her mother. Seeing Perry’s attack on his wife brought up all of her childhood trauma, which helped explain Bonnie’s motivation in killing Perry.

Everything we know so far about Big Little Lies 2