[Multiple weapon mod?]

Are you asking if there's a dual wielding mod? Because that is like impossible in Gamebryo. (or just way too much work for anyone to want to do it)

 

So to answer your question, no.

[Cannot launch NVSE through Fomm]

http://nvse.silverlock.org/

 

Follow the installation instructions, then install Project Nevada. You don't need to launch the game through NVSE, just have NVSE installed.