Dash install noob - Any experts willing to advise?

I have a Nexus 7 (2012) that I want to do a dash install with. I would like to retain my head unit (already relocated) for audio, and I have a few questions.

I mainly want the following features:

-USB Tether

-Bluetooth OBD

-Airstream (or otherwise) phone calls from iPhone through Nexus

-WIFI backup camera

-Bluetooth keyboard?



From what I've been reading it appears Timur's ROM is the way to start. It looks like with an OTG cable and a usb hub I can easily do usb tether.

I have a bluetooth keyboard that has its own USB dongle, I'm wondering if with that dongle I can be connected to the keyboard and the obd transmitter simultaneously

I saw an app that was available years ago to support airstream, but it seems to have disappeared. Does anyone know a way I can have the audio/mic go through my nexus for phone calls while driving? (Right now I use Bluetooth through my head unit)

I found the following parts, is there anything I need to avoid? Or anything I'm missing?

Tendak (Pack of 2) Micro USB 2.0 On-The-Go (OTG) Cord Cable Adapter with USB Power for Cell Phone Tablets

ORICO MPU-5S Auto Universal converter car inverter 12V 5 port smart charger for iphone 5 5S Car Charger Adapter By AFUNTA

Turtle Beach Audio Advantage Micro II USB Analog & Digital Audio Adapter


I'm still trying to do more research on backup cameras, and the possibility of a dash camera. If anyone has any input on any of this I would greatly appreciate it! Thanks in advance and I look forward to being a more active member of the community!