Do you think Buffy meant it when she said she would sacrifice Dawn to save the world? If so, what changed since "The Grave"?
I think she meant that she would be more open to considering it as a possibility, but that in reality she probably wasn't certain what she would do if she were faced with the choice, again.
Was the anger Giles's felt about Buffy removing Spike's chip justified?
I don't understand why Giles would have any more apprehensions about a souled, chipless Spike than he would about oh, for example, a souled ex demon who was just recently killing again. Or, hmmm let's see, a souled, powerful witch who had just taken two human lives. And there's always Faith, the killer. If he was ok having those three around, why would he be worried about Spike? Also, do we really need to count the number of times Spike saved his life (while Buffy was both dead and alive), while he was still
soulless?
Were Buffy's feelings for Spike prohibiting her from making rational decisions about how to handle Spike's trigger?
Buffy's feelings for Spike stemmed from the changes she saw him make. She developed feelings for him when she saw him fight to become a good man. So yes, they colored her decisions, and for good reason. Quite frankly, she was the only one of the lot of them who could see who Spike had truly become. And, you know, that sort of payed off nicely when he ended up sacrificing his life to save the world.
Was it irresponsible of Buffy to believe that Spike could handle the trigger because he had a soul?
Neither Spike nor Buffy believed he could "handle" the trigger, once they found out what exactly it was forcing him to do. That's why they both agreed that the best thing for him to do was to stay chained up in Buffy's basement. Once they took this action, and because of the cooperation on Spike's part, he wasn't responsible for any more killings.
What did you think about Giles teaming up with Robin to try and kill Spike? Were either of them justified or were they simply acting out of their personal hate for Spike?
What did I think about Giles teaming up with Robin to kill Spike? Out of character, nonsense, and a silly plot device. Out of my respect for Giles, I try to forget about it, mostly. I can understand Robin's vendetta. To him, Spike will always be the monster that killed his mother, unfortunately, no matter how much good he does.
But for Giles to try to kill someone who has saved his life so many times (again even sans soul), and has proven to be a trustworthy ally in the fight against evil and in an apocalpytic battle is just so bizarre I hardly know what to make of it.
True, he had a soul, but who was to say for sure that soul was a good one? People do evil things with souls every single day. I think Giles was right to be wary of removing it, and upset that she did.
Yes, people do evil things with souls. But if that's the logic by which the characters should judge whether or not to be wary of one another, why not turn those exact same sentiments toward Faith, Anya, and Willow, who put the lives of all of the scoobies in danger multiple times and had souls while doing it? Why not kill them, in order to ensure that they won't decide to start killing/becoming demons again? Just because they have souls? Well, Spike's now a member of that club, so why should he be under attack in a way in which they never are?
Here's another point: for all intents and purposes, with a soul, Spike is now a human being who should be allowed to make choices. To take that privilege away from him by keeping him chipped, is unjust. Just as Willow, Anya, and Faith are expected to be able to make choices for themselves in spite of what they've done, Spike should be shown the same considerations. And I'd say as far as choices go, he's doing pretty well: he chose to get a soul, and he chose to stay either chained up or by Buffy's side when under the influence of the First, so as not to hurt anyone.