PHEW! It's very likely I'll come back and edit this description later. There's one heckova story and depth to the process of this one! I'm currently pained while typing, and need a break (I did the sketch and lineart for 5-6hrs yesterday, then approx 10hrs colouring this morning).
Though I suppose the MOST IMPORTANT bit is that, of course, the (original) always looks better than the scan.