Teling the target the results is the same as "activating" the Force (if they are FS). Basically you are revealing it to them.
Unless something has changed, you shouldn't need to be partied to use the item on another player; they just need to be at your position.
It makes no difference when you use it. Your facets are determined at the level you become FS in game, even if you are not aware of it. If you became FS at level 1 but didn't test until level 6, you still have the level 1 facets (although facets are going away anyway so it really won't make a difference).