Do you actually believe half of what you wrote, and if so where did you get that information?
The samurai would win simply due to their mentality towards combat. The samurai followed Bushido which taught them to fight to the death rather than face dishonor; whereas European knights were usually hired-swords that local nobles employed.
The samurai were indeed skilled archers, but the yumi was in no way their primary weapon. The katana was, so yes Hollywood did get that one right.Samurai never went anywhere without their katana. Bushido taught that the katana was the samurai's soul and some when so far as to name their swords. Samurai received their first real sword at the age of thirteen and trained with it everyday from then on. And if you have issues with the katana don't forget that samurai were trained in other weapons. Nodachi, naginata, bo, jo, and yari just to name a few. A bo studded with metal would be just the weapon a samurai would need to defeat a knight's plate.
While the Katana could be very brittle if not made right, it was also much much much more flexible than any European sword and would probably bend before breaking.
Plate mail does indeed hinder movement. Carrying all that weight will invariably make movement harder and slower, as well as tiring the wearer out faster. Samurai armor was not made of entirely of steel and was more open in the joints making movement easier and quicker. Lets not forget about Jujutsu either. Most, if not all, Samurai were trained in Jujitsu which was specifically designed to defeat opponents wearing armor.
The deciding factor here would have be modern technology though. You forget that Samurai had access to firearms, while European knights did not. By the end of the 16th dentury Japan had more guns than any European nation.