How might Hagrid come into play?

[A.J.]

No: HPFGUIDX 94935

Hi... So, in his _Hidden Key to Harry Potter_, John Granger explains 
about the stages of alchemy and how we've got Albus as white, Sirius 
as black, and how Rubeus means red so we should expect Hagrid to 
figure importantly upcoming.  Last night I read something that 
pointed out how the Philosopher's Stone was a deep red, and this 
reminded me of how Robbie Coltrane said that JKR had given him info 
on Hagrid's background that we didn't know yet.  Any ideas what we 
might find out or what might happen that would have Hagrid playing an 
important part in the purification of Harry's soul or the development 
of his psyche into an enlightened philosopher's stone, or whatnot?  I 
wonder what went on with Hagrid Senior?

A.J.

P.S., Granger also points out that the key helping ingredients sulfur 
(Ron) and mercury (Hermione) were known as the 'quarreling couple,'  
and had theories on Luna's upcoming importance...