Non-OEM Head Unit questions

Afther my original 2010 Prius gen 3 head unit (touchscreen) died I am in the market for the replacement one.
I have seen many threads about Chinese, Kenwood, JVC, etc. head units but I still do have some questions:
1) What's with the HUD with replacement unit, will it work at all?
2) Does JBL sound work?
3) Does OEM reverse camera work?

Other questions I have found through search, but those are the ones I'm not sure about.