@Marsha-Kay-Ottum-Owen Congrats on selling 50 books! Great going 
Okay, so I had a go at this challenge. I was in the middle of seeing whether I could improve my recent duckling image digitally, when I figured, actually let's use it for Lee's challenge instead - ie doing the reverse challenge version by trying to recreate the watercolour in digital. The original has had the colours deepened with a multiply layer, and a few bits of pencil, but not much.
I started out using the original sketch as a template - as I figured this exercise was more about learning to copy the painting/mark making in a new medium rather than a precision drawing exercise - and then tried to figure out exactly which digital brushes I had which mimicked the watercolour best. This in itself was SO useful - really worth doing - as although I already had a list of favourite watercolour brushes, I hadn't gone down to this forensic level of copying and it really made me dig through and the result is my favourite brush list has had a huge influx of new favourites.
I took a screen shot early on to show the workings out:

And the result (traditional on left, digital on the right):

Thanks @Lee-White for suggesting this!