Going off the assumption that white eyes mean they are at their strongest, then how about we say their eyes are white when they are a wolf? That is an interesting idea, and kind of temping. Though if they can only feed in werewolf form, eating could become very messy. To start off with, they would not be able to compel their victims. Then their teeth would more like rip flesh rather then pierce it. Not to mention, if they are hungry and still have to go through the pain of change it could cause a very temperamental and uncontrollable wolf.

Yes, strength and speed for sure! A werewolves instinct revolves around dominance which is showed by strength and will power. Mostly will power. They also run on pack mentality, you fight as a pack, hunt as a pack, hurt as a pack, and live or die as a pack. Raw meat is was fuels them. Raw meat is to werewolf as blood is to vampire. Also, Alphas have what is called pack magic. This basically means that they have control over the pack, it is part of the pack magic willingly given to an alpha that makes less dominate wolves submit. If a wolf is being dissident, the alpha pulls on the pack magic to boost his or her dominance. It is pack magic that allows an alpha to bring a new wolf into the pack or help another wolf heal faster. It is pack magic that binds them all together and keeps order basically.

Why instinct make up a vampire? I am thinking we can just take the best of both worlds and put them together. And if it a struggle for either of them to adapt, then all the more fun! ^.^