I'm inclined to say fart noise towards all of those claims (except 4 and 6). But, to be fair, I haven't read any science papers in a while, so maybe I missed something.
3 seems the most unlikely, 5 has always been "almost there" it seems, 1 the costs are still staggering and technically the US also wants one, but the return is just so little. 2, maybe small ones? I can see some being cost effective, but certainly not 100s of miles long ones, which is usually what people are talking about when they mention those types of engineering projects.
I have no idea why I wrote these all out of order like that...