I finally got registered on the forum to comment about this film.
First, anyone else notice the Peavey, Cort and Lakland guitars featured predominately in the band? Steve Cropper, Duck Dunn, and Matt Murphy had signature guitars at the time. It was just kind of out of place considering the first movie had them playing Gibson and Fenders.
The Blues have some history with really young blues prodigies. Derek Trucks, Joe Bonamassa, and Jonny Lang were all performing the blues before they were teenagers. If you go see Buddy Guy he usually has some kid playing with him. Last time it was Quinn Sullivan so the character of Scribbles does have a foot in reality. But it's really poorly executed. Are we to believe that Scribbles whole introduction to the blues was through a couple of songs at the Stripster club and a poor sales pitch from Elwood to Willie about getting the band back together? Where did he learn to play Harmonica? They probably could have filled in some holes rather than blowing up the white supremacists.
I read that there was an earlier script where that character was supposed to be played by a down and out 16-20 year old kid which makes sense when Paul mentioned Macaulay Culkin. Even then, my take would to have Scribbles be a student at Columbia majoring in guitar studies where his interest in the blues isn't welcome. He and Elwood somehow meet where he's now the Janitor at the orphanage. After successfully showing the kid 'all the moves' and playing at a blues club for serious blues lovers Scribbles sees an invite to for Elwood to play the Eric Clapton's Crossroads Festival which he's hesitant to play without Jake and his old band. Scribbles reunites the old band and convinces Jake that he should care more about the music than age, line ups, or anything else and convinces him to take his place as one of the legends of blues.