Okay, late to the game but I just watched all of the first five seasons and now I feel like I lost some brain cells trying to put this nonsense together, but god help me, I can't stop watching.
Anyway, I love seeing Red get snippy with Liz. She really needs a smack down by him. I figured that the bones were the real Redington, but I my theory is that Liz did shoot the real Red when she was a kid and for some reason Not Red was there too. Maybe Katerina was having an affair with both men and that is what the argument was about. I still don't know why Not Red and Dembe have such strong feelings for Liz. That makes no sense to me even if Not Red was in love with Katerina. And why would Dembe feel so strongly about her?
Also, Not Red may not be the real Redington, but he has proven himself to be a total badass and made that name one that terrifies bad guys all on his own.