Yet Another Audio 20 Relacement

Ok, I've been thinking about replacing my audio 20 with a pioneer. I have read every thread several times but have some questions. Here goes
Current setup-
Audio 20, CDC, factory Sirius/xm, no phone hardware and non Hk
What I want-
Bluetooth mostly for phone but occasionally use Pandora. I don't care about iPod integration.
Sirius/XM is a must.
Navigation app-I like Waze, and would like it to display on head unit.
Display of email/text on head unit. I would like to use AppRadio or similar.
Backup camera.
The new technology out there is both amazing and confusing. I'm not in need of the latest and greatest and don't wish to spend $1000 on a head unit for a 10 year old weekend driver. I like the Pioneer units and have zeroed in on the AVH-5700, and 4700. I have priced the 5700 as low as $325 and don't really want to spend much more. So as for my questions
Can I use my oem Sirius tuner and antenna with the Pioneer or do I need a new Sirius tuner, and does this apply to all the Pioneer units?
Can anyone recommend other Pioneer units that fit my stated needs and have different or better features? Finally, recommend inexpensive backup camera.
I know many of you have extensive knowledge of all the units available, but the sheer volume of items is making my head spin!
Any thoughts are welcome, and I don't offend easily, so if you think I'm heading in the wrong direction with this, please let me know:smile:
Thank you all