Those blood tutorials are very useful. Even i got a bit of tips from em. I'll share what else I know.
Fresh scars are normally a maroonish with maybe a faded dark pale pink in the middle. Older scars will become more pink until they normally leave a white mark when its sealed up.
If it's a deep enough scar, you might want to reveal a bit of tissue or even bits of torn muscle. Those would be a dark pale pink to red too, depending on how deep. Muscle is made of fibers so its not one solid mass like people think. A reference like the one below should help you with placement and shape. Basically each muscle is strands packed tightly together.
The white area is cartilage and is usually a white as show, though there's no real point in drawing it. It does help with fur shading though.
Ribs are normally thin and there coloring depend on aging. They will be white to a beige and will turn a tanish to brown i wanna say with aging being exposed to oxygen, sometimes with blotches more than others. I'll put another reference for general bone structure below.
Bones in general will have very small cracks or fissures in them. Don't go too crazy with drawing them but a few make it look realistic.
The center of the body has 2 or 3 ribs that do not connect with the rest and are shorter than the rest.
Burns, I can't help much with, but there appearance does change depending on the degree. If I were to guess, it would be similar to scars, but the colors reversed and in bunches and blotches. So a faint burn would be a pinkish and a deep enough one would turn red. (Makes sense since heat makes blood rise closer to the skin.)
I found this thread that might be of some use:
http://alexander-rowe.deviantart.com/journal/How-does-one-draw-burns-279656369Hope this helps a bit. ^^
