Will I have full freedom to use the pCAMBIA vectors?

Without knowledge of the detail of what you are trying to do it is not possible to make any assertions about this and CAMBIA cannot warrant it.  Many aspects of what you may want to do, for example the use of Agrobacterium to transform certain plant species, and some DNA sequences within the pCAMBIA vectors, such as the 35S promoters and the hygromycin resistance gene, are covered by patents that are still valid in some countries (see the technology landscapes on the Patent Lens, covering Agrobacterium and promoters, for more detail). 

Also, although you may have a research exemption or certain aspects of your work may not be covered by a patent in your country, it could be subject to patents where products developed from your work might later be used or exported.  In such circumstances the owner(s) of the patent rights might legally prevent deliverability of the results of your research work.

CAMBIA has developed a plant transformation system that is not limited by restrictive licensing of patented technologies.  If you want to learn more about this, or join in the community of people trying to make it happen for many plant species (it now works for rice, tobacco and Arabidopsis), please visit BioForge and look at the TransBacter project.