In Windows, Cortana can open files: http://www.tech-recipes.com/rx/56615/how-to-open-files-using-cortana/
There are also various programs that have some of the capability you mentioned: https://www.pcworld.com/article/2055599/control-your-pc-with-these-5-speech-recognition-programs.html
Your requirements beyond that seem pretty specific. Your requirements are certainly achievable with software development. Google's API for voice to text can be used to understand spoken words. Those words would be translated to text and could be used to perform operating system tasks. Then, once in the desired state, words could be translated to create content and to further make commands. This is all stuff I'm familiar with. Let me know if you would like more information.
Here's a link to Google's speech API if you want to research it yourself: https://cloud.google.com/speech-to-text/