I have been following this thread with great interest and amusement (in the nicest possible way) about the reptile stuff. Although I have read it in a brief many moons ago, I forgot all the criteria - Breaking News - I am a fellow shapeshifter ;-)
I am O neg, I have low temperature and appalling circulation, a weird back - you could also stick me on a Viking ship in about 700A.D. and I would fit right in.
As for the blood lines - ummm not sure although Mum's family came over with the Norman Conquest but then as you so rightly pointed out so does half the world by now.
Yours chuckling happily