Is Snape a pureblood? and a few other bits Ive been concerned about

[Hitomi]

No: HPFGUIDX 89592

Karen wrote:
> Snape tried to save Harry because he 
> knew that someone had enchanged his broom to throw him off. Snape 
> was doing a counter charm. That does not necessarily mean that 
> Snape knew who performed the initial curse. However, in Harry's final 
> showdown with Quirrel/Voldemort, Quirrel/Voldemort tells Harry 
> that Snape had tried to save him. This produces a couple of questions. 
> 
> *First, did Q/V just assume that Snape was saving a student and 
> not actively working against him? 
> 
> *Second, would Q/V have considered Snape no longer a follower 
> since he was working against him, whether consciously or unconciously? 
> 
> Snape had the interesting conversation with Quirrel outside the 
> Library wanting to know where his loyalties were. Knowing what we 
> now know, we assume that Snape was warning Quirrel not to be 
> working for Voldemort. However, if that is true, Quirrel/Voldemort would 
> now know that Snape is working against him. Snape would be no good as 
> a "double agent". 
> 
> If Snape was warning Quirrel to not go against the Dark Lord, then 
> Snape was and is playing a triple agent game, and cannot be 
> trusted at all. I'm not jumping on the "Evil Snape" bandwagon, but he 
> cannot be infiltrating Voldemort's camp without Voldemort knowing that he 
> is spying for Dumbledore. Either Snape's OotP activies are of a 
> different nature, or he doesn't know that Voldemort is on to him, 
> or else he is actually working for Lord Thingy.

Hitomi now:
Don't you just love how this entire situation that we've been 
discussing is completely ambiguous?!  (And Karen, you brought up 
excellent points I hadn't bothered to think about, thank you!)

The entire situation could go either way, we don't know enough about 
what Snape was thinking, which is the problem in Books 4 and 5, in 
wondering whether or not we can trust him.  I agree, I find it 
highly unlikely LV is completely ignorant of Snape's actions.  It 
doesn't add up with what we know of LV's character, and I rather 
suspect that LV probably suspects anyone and everyone, even Lucius 
and Bellatrix.  Personally, I don't really trust Snape.  He acts as 
a third party most of the time; we never know his true intentions,.  
And we don't know enough about him for me to trust him, I don't care 
what his past, it's no excuse to have ever joined the ranks of the 
Death Eaters.  And I wonder sometimes, being a Death Eater, did he 
kill Muggles and Muggle-borns, too?  There's just too much we don't 
know.  And I know DD and Hermione trust him, but we now know DD can 
make mistakes, and Hermione's trust is based mostly off of DD's.  
And JKR told us to watch out for Snape.  I'm willing to trust him, 
just not yet.

~ Hitomi, who has never liked Snape, but is willing to give him the 
benefit of the doubt