As to Question #3 regarding 64bit architecture, Digidesign said back in March of this year that it was one of the things at the top of their "TO DO" list:
"Going 64 bit is high on our list..."
Now that Snow Leopard is here I imagine we'll see PT taking advantage of the 64 bit OS in
some way in the next couple of revisions. But I also expect it to be a slow, selective, gradual process. And that's not a bad thing, either.