A: I suspect many kids--especially preschool-age children--see dead people. It's a perceptual ability that gets covered over or pushed aside with age and the necessity to develop more left-brained skills. This sensitivity could also explain a certain amount of so-called night terrors and possibly even some imaginary friends. I wouldn't be at all surprised if pets could see this stuff, too.
So I think it's a mistake to think of your daughter as a medium or to emphasize this ability, simply because that would be making her different or special, and that has its own set of problems.
Another concern I have about focusing on this perceptual capability is that instead of supporting her considerable intuitive and creative abilities, it puts a spotlight on one rather razzmatazzy occult aspect, one that unfortunately attracts a lot of questionable participants and fans. As one of my intuitive friends likes to say, "Just cause they're dead doesn't make 'em great company."
So I wouldn't make a big deal of it, one way or the other. I'd treat her comments as possible and interesting, but no more interesting than other things she sees and likes to tell you about. And I'd just try to encourage her to play with and explore her many creative/intuitive capacities, helping her to open and expand herself further in any area of perception or expression.
And in spite of your encouragement, don't be surprised if her ability to see dead people gets submerged anyway, and stays that way for a while. For many kids, a necessary part of growing up in this culture involves putting that level of subtle perception aside and becoming skillful at more concrete social and intellectual pursuits that are valued and needed in life.
If that happens, don't worry. She'll get back to it when the time is right. One of my kids took a detour and didn't get back for 15 years! It was fine. So enjoy her, support her, and watch her petals unfold!