It's an interesting thing about the lass you added color to. What do I think? Yeah, for the most part. But you're at a crossroads and I can see why perhaps you're not sure whether you do or not.
The drawing's good. But you have white where her shadow lines are, like between the nose and mouth. That's unnatural there and a few other places. So that may be throwing you off.
Let me suggest something that would make tinting your drawing easier, where you don't have to have your color fighting your drawing: Leave the drawing as is, and then just go in there and brush in some color lightly, just so as to hint at some color rather than turning it into a painting. You can have a lighter touch that way and the drawing will still be the main part of it. Just a thought. Very subtle color to support the drawing and take it a little further.
As to the other paintings: Van Gogh looks like he's really cookin! You're in the Starry Night zone alright.
PoseDrawSki sez: You're so Van Gogh, you should take care ye don't go cutting off yer ear, ya hear me. . .I said YOU HEAR ME? Bugger. . . does he still have his ear attached? Somebody ask Theo to check on Van Ploos and to bring some Crazy Glue.
As to the geetar! WOOHOOOO!!!!!!!!!! Pluck it, Luther, pluck it! We gotta play while the Maestro paints, oh aye. Very Renaissance, that. Just don't ask me to sing, if ye knows what's good fer ye. No me strongest suit.
ˇVaya con tint that lassie, an' put some rose in 'er cheeks!
"Not a bit is wasted and the best is yet to come. . ." -- remembered from a dream