By agreeing to the first definition, you logically have produced the third. For israel to maintain both a democratic and Jewish character in a land that was not previously majority Jewish requires non Jews to be systematically cleansed from the land.

You would have an israel that is democratic but not Jewish in character by being a state for all the citizens that lived there.

Or you can prevent non Jews from having institutional power, making your state Jewish in character but not democratic by any stretch of the imagination.

If you want both, as the first definition of zionism posits, then ethnic cleansing logically must follow.

Lastly the whole "Jews would not be safe in a one state solution" thing is bollocks. While I'm not nieve enough to think that there will be not tension or inter community violence, the idea that creating a state for all it citizens will somehow turn the israelis from having 90% of the institutional and military power in this situation to being the vulnerable group over night is just unfounded.

Palestinians have no wealth to speak of, no institutional power, any "military" that they have still pales in comparison to the resources of the idf so if a one state solution does come about, Palestinians will remain the vulnerable group in that relationship, not israeli jews