Just got a 2005 ninja 500ex for free!

Well most of it anyway. I was picking up a weedeater I won off of craigslist and while at the guys house I noticed a wrecked bike in his backyard. I asked him about it and he sad it was a 2005 ninja 500ex that his son wrecked. He said haul it off and I can have it. The only thing that is good is the front end.
I have a 78 kz650 c2 I am working on, would the brakes work on my bike? I have dual disc but could I go to a modern single disc?
I think it has a 1\2" bore master cylinder, is this any good for my dual disc?
Are the forks worth looking into?
I am totally unsure but would like to use something off of this bike!

Not sure on the brakes, but what does the fuel tank look like? Trying to modify mine just a little more.

No tank, pretty much stripped to the frame.

pictures of new find?