Is it possible that users up-vote other users more simply because a person has a higher reputation? If this is the case, should there be certain measures applied to counteract this, or to inform users?
I think you may be putting the effect before the cause. Users get high reputation by giving lots of good answers. Don't be surprised when a user who has demonstrated a pattern of leaving good answers gets lots of upvotes for continuing that pattern.
We should educate those coming in, that the purpose of voting is to rate the answer or question. Actually, I think this is already in the FAQ. Education is the key.
You might come up with a modification of the FAQ that would help explain this better.
Yes, but not at a large enough level to worry about. Except on Meta where Jon Skeet gets upvotes just for being Jon Skeet at this stage. But meta rep means nothing anyway.