But Japan had these advantages OTL, and the Dutch didn't care about religion. Meanwhile, the Spanish actively did use religion to further their own ends.
As Nobunaga would use Christianity to further his end in trying to fight his firmly established Shinto-Buddhist enemies while rallying people under his own banner. In this, he and the Spanish are nominally on the same side. The Dutch don't care about religion, but that doesn't help his cause, which is different from the desire for stability and continuity the Tokugawa shogunate had.
Well, Nobunaga was willing to let Christianity flood in if it meant weakening the monasteries' hold on the population. He'll probably turn on the Jesuits in the event he unifies the country, though, or at least removes the monks from his list of threats.
Yeah. Though perhaps by his death, Catholicism is well established?
Of course, this line of thought could also mean that whoever's shogun by that time might, inspired by an Englishman or Dutchman's account of their religion, break away Japanese Christianity from the Catholic Church a la Henry VIII.