Snazzy cool icons, eh?
Monochrome letters not good enough for ya?
Everything except the shiny colourful screen is doable. The screen might be a bit of a challenge, especially considering your last sentence.
However, why don't you list everything you want to hook up and see how much pins it would take. It will get you started.
Monochrome is a bit 90's haha, Dont worrie about my last sentence Ill get there in the end always do....
To control things I was thinking everything can share a common ground, as I would use a simple relay on or off. most relays work with 200mA.
Windows (left x 1 right x 1)
Door locks(all open/all closed)
Rear AC unit
Rear cabin emergency lights
Total of 7 things to switch on/off
Tyres if possible
Engine water tempriture
Engine oil pressure
Fuel filter warning
Diesel tank level
Drinking water tank level
Possibly propain tank level
total of 7 systems to watch with a total of 14 all together. Obviously if some cant be done they cant be done (yet) For the screen Cant I use somthing like raspberry pi thats hooked up to arduino to get the data from then use a UI in the pi to display and send commands back to the Arduino?