I'm sure there would be a combination of apps that could do all of these things.
I don't think you could use both cameras at the same time.
The device would have to be mounted in a position that gave a good view out the front windscreen, gave a good view inside the car, be well visible to the driver, and be accessible to the driver.
My suggestion would be a phone such as an iPhone running everything except the cameras, and a seperate dash cam / security camera. I use an iPhone mounted adjacent to the steering wheel and a Blackvue 650 two camera setup, mounted high on the windscreen.
There are dash cams with maps/gps. I don't think any of them do backup cameras.
There are head units that do gps/nav as well as backup camera, but not dash cam.
Basically you need 2 devices minimum, until car manufacturers get smart enough to build dash cams into the vehicle/head unit or unless you can find a dash cam with open A/V input from the backup camera.