Misty is easy...her EARS! but I dont think I have to point out exactly what about her ears is unique

Happy..hmmm...well the markings running up er face are identical to the ones on her chin, right down to the teeny tiny details

perky has a short smooth soft coat, exept for a strip running down her back which is wire lol

Blair, thats easy he is not a true blue merle, rather then the merling over laying black, the melring is over laying brindle, but according to gentics as they are currently know, one has to be dominant over the other and as such we should only be able to see one of the colours, however Blair looks like a muddied blue merle, with brindle ears, a brindle beard, and brindle streaks on his legs and tail lol

Ripley...uhh well nothing really unique about him lol