Explaining a car voltage regulator circuit
R30 limits the charging peak current to the capacitor somewhat, but at 1 ohm it still allows for 12 A, so of little use there. Also would limit the current through the zener if there are peaks above 20 V.
The larger capacitors work less well at higher frequencies, and that's where the smaller ones take over.  
470 &micro;F in a non-polarized version would be expensive, but there would be nothing against it. All large capacitors are polarized.  
On the output it would give an extra load for the 7805 to charge it. On the input too for the battery, but that can deliver more than enough current.
No, except that they're larger.
Keep in mind that the input-output difference for the 7805 is about 5 V (12 V - 1 V for the diode and 1 V for R30 - 5 V out) and that at 1 A out the regulator will dissipate 5 W, so it will need considerable cooling (sizable heatsink) if you want to draw that much current.