looking at your picture again i'm a little concerned that you might have joined parts that shouldn't be joined... it might explain why your model bunched up when you tried to relax it. the attached image shows what part i highlighted and joined... after its joined there was no crossing lines in the leg area. if you join the wrong points... when you relax it it will try and pull the parts over to the sides it thinks it should be on, i guess would be a way of explaining it... and now would be the time to mention that cutting the jaw from the head would make things easier too later in the mapping... but thats just from my personal experience. you can just lasso the jaw on the right side of the screen on the model itself instead of going all the way back to the uvmapper stage.