Not only do I not have that (as synaesthesia -- I can still have vague mental images of my limbs the way I can with anything else), but if I lie with my eyes closed long enough (say, more than half an hour) I kind of forget which way I'm facing -- though I suppose this description wouldn't really make sense to people who haven't experienced this.

No idea, people i ask irl don't have it. I thought everyone had it.