I bet this is just a hypothetical question, and 90% of chance the owner is not going to implement it even if someone provide him a comprehensive solution.
Sorry, no offense intended.
If you are using your car more as a science lab and not as much for commute here is a suggestion from my end. 1)
Install a Push button start mechanism for your car. Something like this 12V DC ENGINE STARTER IGNITION PUSH BUTTON SWITCH WITH RED LED 2)
Get a GSM relay control board. Something like this 2 Channel-Wireless GSM relay board remotely switch ON-OFF
Make sure the relay contact rating and starter switch Amp rating are matching. 3)
Take a pair of wires and connect the relay contact terminals in parallel to the push button, just like another switch. (Incase if you get into an
out of coverage area you can start with push button too
). Connect the GSM relay unit to 12V supply in car, grab your mobile, pair it with the GSM
relay unit and we are ready to start.
I know this is a very crude design, but I couldn't come up with anything better. No brickbats please!.