In a multiplayer game, if a player leaves the game, all cards that player owns leave as well, and any effects that give the player control of permanents immediately end.

Gaining control of an Equipment doesn't cause it to move, though it will allow you to activate its equip ability later to attach it to a creature you control.

If one of the target permanents is an illegal target as Shrewd Negotiation resolves, the exchange won't happen.