All items that are capitalized in-game we capitalize; therefore, Choice item, status Orb, Ball (as in Poke Ball, Master Ball), etc. are capitalized no exceptions. Never capitalize "item" though, and remember that Berry is also always capitalized.
Instead of Rapid Spinner or whatever, please use either just spinner or Rapid Spin user, Pursuit user or trapper, etc.
WishPass refers to the combination of Wish + Baton Pass, but if you're simply passing Wishes (ie. with Audino/Chansey) then it is called "Wish passing"
Also I might as well drop this here too: it's called Extreme Killer Arceus, not Extremekiller; when firecape, Tmon, and the Uber crew coined the term they wrote the analysis using "Extreme Killer" so that's what we'll go with.