Before the first film, I had thought that Billy Connolly would be a perfect Hagrid, but Robbie C does a great job.

I don't think it's possible that the "eulogizing" at the end of the movie can have anything to do with future deaths; the people who wrote the screenplay will surely not have been told secrets about the future of the story; this is how leaks happen, and the publishers and Rowling will be very careful about this. Hence, they almost certainly don't know if Hagrid is going to die.

My own feeling is that Dumbledore may die before the series is over. Certainly, he is the logical character; the master/mentor figure in mythically-structured tales is usually killed as the hero matures (Obi-Wan Kenobi, Qui-Gon Jin, Yoda, Gandalf [though he returns], etc) But Hagrid, being younger, would be more of a shock, so she may opt for that.

Of course, the most under-used cast member is poor John Cleese, who just floats around saying "hello" to people. Hopefully he'll have more to do in future films.