I know this is a weird thing to upload, but this is the color palette I use for my pictures(well, sonic pictures). Anytime a pastel color is needed, this comes out. Well its actually modified a bit to look more like an actual picture (it used to not have the classic sonic) but since I still haven't done a Sonic Generations thing yet, I might as well try here and please try to bear with me, I'm aware that I'm not exactly familiar with how to draw Classic Sonic, as I dont really practice him as much, but I tried Also, this thing isnt very recent, it was done awhile ago for pictures with pastel colors, so the drawing style might be a little old here
I'd say you got the design of Classic Sonic down pretty well- better than what I could do! I especially like Modern Sonic's noodle like limbs, it adds a cartoony feel. The colors are really sort and pretty, too.