I have a question. Is the Product/ System Solution Vision and the Product/ System Solution roadmap one and the same thing? And which comes first, the Product Vision or the Product Roadmap?
Product Vision and Product Roadmap are not CMMI terms. So, in the context of the CMMI, simply use the standard dictionary definitions of vision and roadmap and you should have your answer.
The way I look at these two concepts is that vision refers to what you are supposed to achieve and roadmap is how you get there. Therefore vision would come first followed by the roadmap.
The bottom line is that you should define these terms for your organization if you think that they apply and are important.