Is C::B will change to wx2.7.0?
As a general answer, not only for 2.7.0, but for all upcoming releases, it has to be said : no.
We're not switching to a new version of wxWidgets the day after it is released. We have not before and we will not in the future. While we have done so for other third party libraries (for example TinyXML and Scintilla), wxWidgets is not a particularly backwards-compatible thing. You can replace TinyXML 2.1 or 2.2 with 2.4 in about 10 seconds without changing one line of code and without having to worry about breaking anything.
The same cannot be said about wxWidgets. Upgrading to a new version of wxWidgets usually requires numerous code changes, and you are not even guaranteed it works.
Before we can possibly switch to wxWidgets 2.7, we will have to wait until the usual bugfixes are out so it is actually usable, and then we will have to implement the necessary changes and we will have to thoroughly test whether it really works for us. If we switch to 2.7 one day, this is at the very least going to take several weeks.
And what time RC3 can be out?
A similar answer applies: when everything works as we want it. Not before.
This relates to not just the Code::Blocks application, but to several organisational things as well.