Unanswered questions for SS/PS Was: ADMIN: What should we do next?

[Carol]

No: HPFGUIDX 185324

Sheryll Townsend wrote:
 <snip > What do we do next? 
> Should we start over from the beginning with new chapter discussions? 
<snip>
> We'd like to hear what you want to do next! Obviously, Main is not
the right place to discuss this, so we'd like to open this question up
over on OTC. Please, come on over and let us know what you think!

Carol responds:
I know that you moved this discussion to OTC, but I'm presenting my
"modest proposal" here <winks at eggplant> in hopes that it will start
a new thread.

After rereading the books post-DH, many of us still have unanswered
questions for each book, even SS/PS. So here's my question, focused
for the moment on SS/PS:

Which events still remain open to interpretation because JKR never
fully explained them or left them to the reader or provided
inconsistent information later? 

When the thread is exhausted for SS/PS, we can move on to CoS, asking
the same question, and from there through the other books. I'm sure
that others can think of similar or better questions of the same sort
about the earlier books, either posting them in this thread or
starting a new one.

I'll start by presenting one of my own questions about SS/PS. Did
Snape use either Occlumency or Legimency or both on Quirrell? How much
did he know? (I realize that he answered the question for Bellatrix as
he had done for Voldemort, but he was concealing his later use of
Occlumency against Voldemort.)

I would welcome responses to my question, realizing that they can't be
definitive, as well as questions of the same sort by other posters.

Carol, who may think of other unanswered SS/PS questions later but
hopes that this one will do for now