I simply would not GM for that group. Friends or not, it does not sound worth the headache and the inevitable arguments. That altercation that happened before, I would expect that to happen again, and I wouldn't put myself in that position. Gaming is supposed to be fun, not a second job that occupies a lot of time and doesn't have an enjoyable payoff.
shes also voiced a dislike for guns (her current character in our current game wont use them), which can be abit of a crippler in SW really.
This is actually the easiest thing in your post to work around and possibly fix. Meleeists are extremely viable in Edge, even without lightsabers.
And if she was burned by Star Wars RP in the past, I would bet it was either WEG or d20, neither of which is near as narrative a game, which can be quite a bit more fun than a rules-heavy one.
I'm afraid I have no good advice, I just wouldn't argue. I'd tell him bluntly I'm having a sh*tty time and it's because of him and if it continued I just wouldn't play.