I see no civil war in the cards anytime soon. We have serious issues but civil war isn't likely at all. I think its more likely to happen in the U.S than in Israel actually. I hope it doesn't happen in either place.
I think the reality is that at some point the Israel government is going to have to become a fully secular democracy. Do you think that can happen within the existing governmental system or will it require a completely new government?
I'm not sure what you mean.
Do you mean Israel needs to cancel Zionism and become open for Palestinian immigration (e.g 'Right of Return')?
Or simply become a more liberal version of the current Zionist system?
The second is possible in the next election, people are sick of Netanyahu and his cronies.
The former since that would be the definition of a secular democracy. The same immigration and citizenship laws regardless of religion or ethnicity. There's definitely need of some reparations as well, so I think right of return would play a role in re-establishing the Palestinian population from where they were displaced.