Recruited through a staffing agency. First stage of inteview process was a panel phone interview with 4 people and me (the employee I'd be replacing, an employee who shared the position, and their two managers). After passing this phone screen, I was called in for an in-person interview with the same group (2 in person, 2 on phone). One week later I received an offer to take the position as a contractor. I contracted full time for almost 1 year then "interviewed" for the permanent full time position. I met with my coworkers for this interview which was rather informal since I'd already been working with them all for almost 1 year.
The interviews were standard. A lot of behavioral type questions about how I would handle certain situations. A lot of involvement from the interviewers telling me more about the position so I could hypothetically respond to how I would react.
There is no one work culture at KP; it differs from department to department, so no overall advice. In general though, I do think they they like to practice what they preach in re the Thrive branding messaging. They do like to see that future employees have a good work/life balance and are passionate about good health and the mission of KP.