To me, Halo still sounds a lot like the "old" Linkin Park. The power chords used during the second half of the song are almost the same as what they've done in songs like Numb, Easier To Run,...It's the "using power chords to make a chorus big" phenomenom Mike was talking about recently, IMO.
Then, you'll say "the demos you want are supposedly heavy, they have power chords man!". Yes, but the guitars in GU, NMS, and Qwerty are way more agressive and rough(sonicely) than before I think, it's different. I mean, before, LP already had heavy riffs, but the sound of their guitars was more layered.
About She Couldn't...Hum, yes, you're right. But I will not be objective by saying at this moment, as LP is realeasing soft stuff again and again, I'm more attracted by their heavy side. It's a matter of taste, and I respect your opinion.
Not sure, but I Think those crazy ideas would have been incorporated in their "Nu Metal" sound, label or nor not label. At this time, they wanted to proove their HT success, so replicate the same sound, and Chester was quite angry and drug-addicted, so he would probably have continue to use his "hardcore" HT vocals I guess. So, all in all, a sound similar to Meteora, maybe with more experiments. But not sure, just a bet...