Great questions!

It's important to note at the outset that an investigation into Druze opinions requires access to a type of deliberation always available or accessible. However, historians examining the 1947-49 wars have noted that Druze villages appeared to side with Jews more often but were not unanimous (as anyone could expect).

The original view of many Druze villages was to stay out. Some assisted Jewish forces during the civil war portion, prior to the Arab intervention in May 1948, but this was done primarily out of dislike for their Arab neighbors, or because they felt Jews would win (or at least, win in their area). This was not due to a lack of connection between Druze villages and Arab military forces; people like the Arab military commander Fawzi al-Qawuqji had participated in Druze revolts against the French Mandate, for example. The Arab Liberation Army (ALA) also put together a Druze battalion during the war. The IDF did the same around the summer of 1948.

While the ALA had a Druze battalion, it was largely independent from ALA command. It even negotiated covertly with the Haganah Intelligence Service (the main Jewish fighting force prior to consolidation in the IDF), in case it wanted to pursue peace. The Druze villages and leaders seemed to be especially sensitive to picking the winning side in that regard. Nevertheless, one particular battle during the 1947-48 civil war period made a particularly large impact: the Battle of Mishmar Ha'emek.

The ALA had commanded the Druze battalion to begin operations in the area around Haifa, in Israel's north. The Druze battalion began to operate, and faced off with the Haganah. The Druze battalion had shelled kibbutzes in the area, so the Haganah overran the villages of Hawsha and Khirbet Kayasir, and refugees fled. This loss would put a major dent in Druze morale, and they were infuriated. So they assaulted the battalion-sized Haganah force the next day, and Benny Morris writes in 1948 that they advanced "with large knives sparkling between their teeth in the sunlight" (quote originally from the Haganah's history of the war) a total of nine times. After the first few, it became as much about extricating wounded soldiers or dead bodies as it was about trying to seize the area, so fierce was the fighting. The Druze battalion asked for mortar support, and the ALA sent a handful of mortars, with only 1 in 10 of the shells even workable. The Druze battalion ended up losing 24 men, and more than 42 were missing. Dozens of local Arab militia were also killed in the fighting, having joined the fray, while only 19 Haganah troops were killed. While the Haganah wrote praise of the Druze battalion later, the Druze battalion's morale shattered. They wrote that they had only 190 soldiers left of 500, that the morale was very low and that local militias were more and more cooperating with Jewish forces because they didn't think they'd win.

When the Druze battalion's commander asked for support from the ALA, even while he himself was negotiating with the Haganah secretly, no answer came. By the summer, when Israel was setting up the Druze battalion of its own, this was in part because the Druze communities of the area felt increasingly certain that the battle demonstrated that Jewish forces would win.

Thus, a string of Druze villages at that point threw in with the Jewish side, and many of their irregular forces helping the ALA deserted. The Druze villages in the western Galilee were, as a result, "conquered" with ease.

This cooperation continued throughout the war, and reinforced itself over time, likely forming a foundation for future cooperation. When villages were captured, Druze militia who did not participate in the fighting (or who avoided it as much as possible) were left armed, while Arab militiamen were not. When IDF forces came across Druze travelers, they often left them alone, while they would often search Arab travelers for weapons. Druze forces became attached to larger Israeli forces as the war went on and Israel was declared, beyond the Druze battalion, and served with distinction. One auxiliary Druze company, fighting alongside a larger Israeli battalion, was ambushed by an ALA unit and local militia in October 1948, and forced to retreat, but the Druze suffered 11 deaths, while 3 Jewish officers died, demonstrating the commitment of Druze forces to fighting alongside Jewish ones. However, again, this was often subject to proximity to Jewish villages and forces. If Druze villages were well within Arab militia zones, they did not seek to get engaged where possible. If they were members of Druze-Arab mixed villages, they frequently sided with the Jews, but did so covertly, due to histories of conflict. Prior to the war, both sides were courted, particularly in areas that were more borderline between the demographics of surrounding villages. After the first truce, and the losses of Mishmar Ha-emek, the ALA's Druze battalion was left without about 50 men, while many of the others had return to villages in Jewish-held areas. Many of those areas contained villages that, at the start and preceding times of the war, had been courted by Jewish leaders. While the ALA and Arab leaders generally attempted to use intimidation, threatening to investigate connections to land sale to Jews starting around the mid-1940s. This ended up backfiring; the Jewish forces were aware of Druze participation in Syrian fighting, and feared it, so they tried incentives, and also subterfuge. The Haganah's intelligence services learned of divisions between various villages and attempted to play them off one another, while ultimately hoping to unify them under Jewish force banners.

To take a step back for a moment, the relationships in general began following the 1929 Arab riots, as well as the 1936-39 Arab revolt, during which they solidified. Jewish forces were well aware that the Druze were a potential ally, as a minority, and believed they would certainly be a hard enemy to overcome in addition to the already-larger Arab population and Arab states surrounding them. But the ties took a long time to cultivate. Two Jewish officers in the intelligence services would meet frequently with high-level Druze contacts, and try to get an understanding of the intricacies of their cultural differences with Arab villages, the historical troubles they had, and what developments were ongoing to affect those relationships. These meetings grew gradually to include additional high-level Druze officials, who were drawn in by those initially met. Lo and behold, one of those brought in later called a meeting of Druze notables in Haifa, and persuaded them to strengthen ties to Jewish institutions, and to cease to rely on Arab ones. The Arab leadership, upon hearing of this, employed the pressure tactics I mentioned. They showed photos of the Druze leaders selling land to Jews, and threatened to take action. Jewish officers similarly tried to pressure the Druze leaders, but they did so by saying they wanted more benefits from the relationship, and asked them to establish covert associations for Druze-Jewish relationships. This was much more appealing to the Druze village leaders.

Ultimately no such association or meeting of villages occurred, but the mere fact that the Druze leaders went around asking if villages would be open to it, and villages expressed interest, indicates how far relations had come before the war. The Jewish leadership had been prescient in that regard, and it left the opening for Druze defectors and a better relationship. In short, Jewish leaders knew that they could build on Druze dissatisfaction as a minority, and they took the opportunity to learn about it, and used what they learned well.

As mentioned, this was not universal. The Jabal Druze, largely in Syria, were negotiating separately with Jordan, so the Jewish forces were unable to get any headway with them (they wanted Jordan to annex their territory). The same was true of attempted connections in Lebanon, which failed. But Israel had sought to work with Jordan's king already, which it felt was virtually the same in the end if an agreement could be reached for Jordan to annex Arab areas of the British Mandate.

When that additional bullying began, where Druze leaders were threatened once more by Arab leaders in early 1947, was when it really backfired. The Arab leaders intimidated the two Druze leaders that Jewish forces had been meeting with, and the two Druze leaders took their complaints of intimidation to the Jabal Druze leadership in Syria. The Jabal Druze decided to side with their Druze brethren, and told the Arab leadership to stop bullying the Jewish-aligned leaders (not knowing, perhaps that they were Jewish-aligned of course). The Arab leadership then tried to take their message directly to Druze villages, telling them not to sell their land to Jews, which was unconvincing: Druze villages were still more than willing to make money selling to Jews, and did so. These tensions continued to grow throughout 1947, and no doubt made the decision to side with Jews much less ideological than it might have been in 1921, for example.

Thus, the combination of Jewish strength, coordination in fighting, and history of attempting outreach to the Druze that was conscious of their internal divisions and cultural distinctions, made a pretty distinctive success possible. Of course, it laid the foundation for the relationship you see later on, which while imperfect as any state relationship with minorities is, is much stronger than it might have been without that initial understanding.