for a fade effect you'd need to use a capacitor and transistor. that's pretty easy to do as well.
it's a more simplified version of this circuit
That wouldn't be bad if his desire was for the LEDs to be on 100% of the time while the VX is running and then just stay on for X amount of time after he shuts it off.
If the intent is for the LEDs to turn on when the VX is shut off and remain on for a minute then the 555 is the more appropriate option.
As for Dome lights.... most of the time the timer is built into a special relay that controls all of the interior lights, not just the dome light.