I'm not exactly sure as to what they are telling you. It could be that they are assuming you want the OEM camera to display on your Pioneer and that's not possible. As it was explained to me, the OEM camera is digital and the Pioneer wants to display an analog signal so they're not compatible. Take that with a grain of salt though, as I've been told all sorts of things that turned out not to be true - The Crutchfield 'expert' told me there was no available harness which kept my OEM back-up camera, but that turned out to be wrong
I'm 99% sure the XSVI-5524-NAV harness will install your Pioneer correctly and retain the stock back up camera . . . . . but I'm not sure if adding the ASWC-1 harness to retain your steering wheel controls will keep the camera functioning or not - Maybe not
Worst case, adding the ASWC-1 harness to get the steering wheel controls operational costs you the OEM back up camera and you end up installing a new $50 camera and route it direct to the Pioneer
My van did not come with OEM steering wheel controls, but I later installed a very nice OEM leather wrapped steering wheel which does have them, but because the van did not come with them, the computer isn't programmed for them to work - They didn't work with the OEM radio before I removed it and adding an aftermarket harness in an attempt to make them work didn't do the job with the Pioneer either. I'm fairly sure I can 'tag' the wires under the steering wheel and route them direct to the Pioneer and get them to work, but I haven't got around to confirming that yet
Yes, your Bluetooth and Sirius will be a function of the Pioneer when you get it installed - New microphone and Sirius adapter will be required
Good luck with your install and please post your results here - Every bit of new info will help the next guy
Don