Re: dashboard rattle
I had a rattle with our RHD export CRD that turned out to be the windscreen vent in the far top corner of the dash LH side. It would disappear when the passenger put a hand on top of the clipped in plastic - lifted it a bit and stuck some double side sticky tape under and reseated. Fixed it.
I didn't have a go at it until after I reported it to the dealer (plus my thoughts on what it might be), the tech checked and reported that the aircon pipes inside the firewall in the engine compartment were touching and making the noise. Showed .45 hour on the service docket to diagnose and adjust (under warranty).
Needless to say the noise didn't disappear or change.
I think you are right to do some homework yourself.
2015 Laredo CRD
Billet Silver with Quadralift, front recovery hook, Mopar towbar
Upgraded from 2012 CRD that did the job brilliantly for 4 years
1975 Holden HJ 308 Monaro 4dr - oldie but a goodie