Great idea!,
that's what I wanted to do to a 86-87 Ninja if I start another project. You swap the whole front end, triple clamps, forks, bars? Any clearance issue? Did you keep the stock swingarm or use an 08-12? the swingarm pivot axel diameter is smaller on the 86-87 but there is a sleeve/spacer so if you swap over the everything it should work, unless Kawasaki up the axel diameter again on the 08-12 250.
Green is "Kawasaki" color but hard to pick a shade that looks nice. All the lime, neon and in your face green that Kawasaki race team's use seem to lost a bit of wow factor when applied to vintage machine. White compliment green so find some way to introduce white into the machines, either wheels or decals will balance the green out. Keep going, your almost there!