There are a few bits, like his comments on Annie’s death and the “God I hope this works” line, that imply that he was actively trying some sort of solution, but I suppose that doesn’t necessarily imply that it worked, whatever it was. Or maybe it’s all just referring to his locking up the computer and making a list of people who weren’t allowed to access it.
I think we can pretty definitively say that. We know that the deaths stopped after Longley’s, because he was the last one and no one remembered him. If remembering previous victims were still dangerous, then presumably people would have kept dying. In fact, the deaths would be increasing exponentially. (And it wouldn’t make much sense to talk about a chain otherwise.)
Yeah, I think this is correct.
I think that the solution was simply “let the last person to die be a loner who’s unlikely to be remembered”. He knew that investigating the case was likely to lead him to remember someone (it seems that the curse had reached the police force by then, so he knew he’d likely known some of the victims) and deliberately kept going so he’d be the next in the chain.
[@] I guess this is what everyone was expecting. No one ever said it out loud, but I knew what I had to do. I was your only choice. No one’s as disconnected from the outside world as I am. The fate of the world on my shoulders.