Trust your installer.
I have a Sony XAV, replaced my BOSE, and with a couple of basic adapters, everything works.
If you think for any reason that it would not work...contact Crutchfield (online Chat)
They sell the same head unit online that you just purchased.
Ask them to give you a quote for everything you need to hook up to the factory stereo, and they will not only tell you what you need, they will also include the wiring diagrams on how to do it.
Then go to your installer and compare notes, and you will know that everything will work.
Crutchfield know their stuff. They are almost legendary in the radio business.
If they tell you, you can't do it, they are probably right.
I have a Sony XAV replacing my BOSE (with Sub) and I have integrated the rear camera no problem. That's a seperate thing to tie into, at the reverse lights. Make sure to know if your new head unit had parking lines built in.
I've installed this MYSELF and I didn't know much on how to do it. If I can figure it out, a radio installer would know for sure.
I have Andriod Auto working, bluetooth and everything. No problem whatsoever.