Question: Does Nick Nack die? Did he suffocate in the suitcase?
Question: When Bond goes to the fighting ring and discovers that Maud Adams is dead, was that really a dummy of her? It sure looked like one to me.
Chosen answer: No, it was the actor.
Question: Where is the golden gun now?
Answer: I haven't been able to find any information on its whereabouts so my guess would be that ended up like most movie props do. Either as a souvenir for one of the people attached to the movie, (actor, director, etc.) in storage (in case it could be recycled as a prop in another movie) or simply discarded when it wasn't needed anymore.
Question: Why can't Scaramanga see the solex on the floor after he kills Miss Anders, as Bond sees it easily?
Answer: He is a trained killer and like Bond he must watch his back at all times. He was so busy looking around for traps and other agents, that he didn't notice it. Bond, however, is trained to observe everything, his main focus was to find the solex.
Question: Why did Hip and his two nieces leave Bond behind at the karate school? Didn't the nieces let him know that Bond was running behind?
Answer: Hip gets in the front and the two nieces get in the back and Bond slams the door shut as he passes to get in the other side, Hip naturally thinks Bond got in the car after hearing the door shut so drives off. The two nieces are shouting at him and for some reason ignores their pleas at this point Bond has to make his own escape.
Answer: Simple misunderstanding. The two nieces were attempting to tell Hip but he thought that Bond had gotten in the back with his nieces. That, or he wanted to spare the innocent parties harm, so he split up from them.
Answer: Likely not. He's still screaming that he'll get Bond as the junk sails away at the end. Presumably, either he and Bond came to an arrangement after the film or Bond turned him over to the authorities. At the VERY end of the movie you see Nick Nack is actually suspended high on the mast of the junk.
Captain Defenestrator