The primary difference is the level of automation available during the authoring process. However, both tools produce the required EFS submission files. Yes, as long as the content of the original specification document is not modified in anyway. The applicant will be careful to avoid adding any new matter to the application in the process, except for headings and other organizational indicia needed to fit the EFS requirements for submission. Cutting and pasting is a huge problem with large documents.
Large documents translate rapidly using cut and paste.
Opening a file written in another application would not provide the detailed XML tagging. As new automation technology is available, it will be applied to the authoring tools. Most likely, this will occur after EFS development has been taken over by third-party software vendors. Documents can be retyped into the authoring tools. Yes, as long as they are using the same drive letter, directory, and file names on both machines if storing files on network drive.