Hi @AnnieM have you ever found a resolution to your squeak/chirp? I have the same issue! I thought it might be the car seats, but at some point I didn't have the car seat in and it still made the noise. Especially on turns.
I'm hearing a squeak/chirping noise from the rear seat area when I drive on a rough road. Dealership tells me they can't replicate it, but I video'd it and let them listen to it. At one point they tried to tell me it was a loose headrest :-(