The answer to the first question is a definitive YES. But since I have not tried everything to make sure no regression, I will suggest you to use the solution with care (if you run info some DLL not found, that would mean this solution is not adding some paths to PSSE).
Ok, here we go.
Firstly, you can get the gist by just right click on the PSSE shortcut on your desktop. It should be something like this:
"C:\Program Files\PTI\PSSE33\PSSBIN\psse33.exe" -ini C:\Windows\psse3304.ini -pyver 27
What this means is that, the shortcut calls up psse33.exe, with the options of:
- -ini, and the path of the ini file that configures PSSE
- -pyver, the version of Python, which is 2.7 here
If you run this line of code in cmd, it will start PSSE with nothing loaded, just as double-clicking on the shortcut.
If you open the INI file, you will see the whole config. One noticeable is the "PATH", under "STARTUP". Therefore, we can deduce this code:
"C:\Program Files\PTI\PSSE33\PSSBIN\psse33.exe" -path "C:\Program Files\PTI\PSSE33\Example\savnw.sav" -ini C:\Windows\psse3304.ini -pyver 27
What this code does is to call up psse33.exe with the options of "-path", "-ini" and "-pyver". This would start PSSE GUI with the example "savnw.sav" loaded. Tested on Windows 7 with PSSE v33.4. You can look into the INI file more and play with the command line swtiches.
For the second question, I think it is interesting, but I am not sure. I think you probably would not have the same instance, but might be able to sync the state to some extent (version dependent). What do you need the GUI for? If you can Python stuff, why would you need the GUI?