1) all you have to do is check for specific conditions and then apply whatever animations etc you want under each condition.
eg: Add an event that has Keyboard left arrow is pressed, and add a second condition (right click-> add condition) and pick keyboard up arrow is pressed.
Now those actions will only occur when both keys are pressed. Rotate the wheel's or play a different animation direction or whatever. Do the same for the other possible key combonations you want.
2)I can't see the capx right now at work, but it sounds like you just want the car to scale depending on what area of the screen its on. Simply add a "system every tick" event, that scales the car based on its Y postion on the layout. You might need to get fancy with the math to make it scale nicely at any height. I suck at math so perhaps someone else can help with that.
3) use "on layout start" -> set animation to "standing animation"
ideally put that event at the beginning of all of your other events.