I am not involved in Beta this year. So take what I say for what it is worth.
1) For Java people. They are going to a later version of Java (8?). So you get the new features in Java. I think they are focused making the new software & hardware work. Don't expect a lot of new features. The supported 2015 platform is Eclipse. Doesn't mean it cannot be made to work on other platforms, but you will be on your own.
2)
Here is the other Frank's blog on beta teams. It lists the location of the teams. The 2014 plugins where released at kick off. The 2014 getting started guide tells you how to get them. First only knows when the 2015 software will be released. I expect at the earliest in Dec when the preorder Robio Rios ships. More likely kick off. One reason is First doesn't want pre release versions floating around. Yes Beta teams have the Beta Plugins. Assuming the NDA is like last year, they can show you code. Show you the IDE complete with plugins. Let you help develop code on there system. They cannot give you the plugins. Would not be useful without the new hardware anyway.
3)No nothing out for the new control system except what the Beta teams publish. See above.