He does own the copyright on many if not most of the GNU tools that Linux needs to operate. As I already mentioned above the developers of the tools signed over the copyrights to him as the ultimate tribute of their work to his cause. See post 16 from someone else for more info.
1) He owns no copyrights in the Linux kernel.
2) He cannot retroactively "unlicense" anything previously released with a GPLv2 license. The only thing he can do is "fork" new development, in which case, as I poitned out earlier, the "v2" folks are going to win over the "v3" folks because the majority of folks using the programs are doing so on systems that will be incompatible with GPLv3 (unless they're running something obscure like HURD).