Fark Karate Kyle

A poor attempt, but posted in hopes to get an answer to this question:
To anyone who uses GIMP:
What's the best way to select things around the edges for colorizing (when I try to use scissors, I can't select the bottom right/left edges to change the red to purple).

I use Paint.net and this doesn't answer your question, but this is not how I would personally edit this image.

I would make a copy of the entire layer and change the hue and saturation until the red matched the purple. The only problem is the rest of the image is now also a purple tint. I then would use the transparency gradient to carefully erase the face, hands and background. Then the original layer will be visible.

The way you are doing it will take quit a bit of masking and a lot of work if you are inclduding the background uniform.

The only problem with my method is it is very difficult to get yellows to match correctly and appear as if they weren't 'shoped.

Winner.