I think it would be better to use Katanas on this stage, since it is more effective because of the larger sweep radius of its attack. But I guess this is ok too, since you need a fast DPS weapon against the King (Hammer works well too)
1-i do now since like last week, this vid was made like a month ago, and im on skies of crimson (killerluigi) look it up
2-nope the master swords
3-i know but if i put me fighting 15 skakas it would be less interesting