Here take a look at these.
This is fairly obvious Yuki drinking blood with the reflection of zero pointing a gun at her. Also what you just mentioned about the Knight think about Zero's heritage.
This is the major one that took me a min to put together. First look at what chess piece is used and now think about we just found out about Yuuki in the recent chapter including her and Kaname's blood line. Next, look at how the chains are almost BINDING or SEALING around Yuuki. Now think about what her mother did to save her life in the past.
These scenes make me think the animes is going to follow the manga almost exactly. The second image takes a bit to think about most people missed it because it goes by so fast in the OP.