I must say that costume looks great, it is alot better then most of the cos-play pictures I have seen, and I love the detail that you put into his gun and from I have seen the claw looks fantastic also.

Also with the Cloud costum I would recommend sticking with his original costum from FFVII, or if you are up for the challenge the one from kingdom hearts II would be amazing to see. (Sorry I can not supply pictures into it right now)

As for the sword for the costume since it will be made to scale for him (I presume on this haha) I would just make it for visual purposes not for play, anything that he could play with would be way to heavy for him to carry around with for a night haha.

I have never made a sword before but I suppose that you could use PVC pipe for the handle and Foam for the main blade sections of the sword. To give it that metal finish you could always take aluminum foil and scuff it with scotch-bright to dull it down and then glue it on to the foam. It would crush if it takes any kind of impact but it would be light enough for him to carry around all night and not have to worry about his arm falling off from the weight haha.

Any which way it goes keep us posted I think we all would love to see what comes of this.