And if push came to shove, do you think the bolshevik Israeli soldiers would actually fire on their fellow Jews?
In my mind, there are 4 types of people who might do it:
1. Part of native Israelis (sabras) who believe that the order of their commander and the state is saint and it is required to fulfill the order without thinking. The problem here that in most cases soldier really must fulfill the orders even if it contadicts his opinion, otherwise the army will not function. So in this case a soldier who doesn't have strong Jewish background may really fail to draw a border between the importance of military order and its moral validity. Also take into account that the soldiers who are sent to such missions are beforehand brainwashed that the settlers are cruel savages and fanatics who oppress poor Palestinians and do not recognize any law.
2. People of any origin who are only occupied with thier own comfort. They will never do anything that may harm their reputation in the eyes of their commanders (and do everything to earn such reputation), let alone the possibility of being sent into prison for not obeying the order.
3. Some immigrants from the former USSR who are Jews by Halacha but really Russian/Ukrainian/etc. by mentality and world view. They are friendly to all Russian (language, culture, traditions) but hostile to all traditional Jewish and Israeli. The reason why they moved to Israel is purely economic - seeking better life - but not national or religious. That's why I call them immigrants, not olim. Yet they feel themselves Jewish and may hesitate on whether to fulfill a settler eviction order on the basis of national solidarity ("he's a Jew and I'm a Jew..")
4. Some immigrants from the former USSR who are non-Jews by Halacha. They are similar to group 3 but in addition they don't have any national sentiment to the settlers because they are Jews. Moreover, there are some who are real antisemites and even neo-nazis (!) and would volunteer for such a mission and fulfill it with ardor and joy.
P.S. When speaking about groups 1, 3, and 4, it is important to notice there are many exceptions from them.
P.P.S. As for Israeli Ultraleft, I don't think there many such people in Magav and Yasam units that are usually used for such actions. The leftists consider themselves elite and don't send their sons and dauhgters to do such a dirty job. They rather plan such actions on the levels of state, legislation and military command.