I just put this same kit on mine Sunday. I do not have 2" spacers though.
No the kit does not come with longer brake lines, it comes with brackets to extend the brake line mounts that are on the axle at the lower control arm pockets. I would think getting some longer brake lines or making some brake line mount extension where the line is bolted to the frame would be necessary for the additional two inches, but I don't know for sure.
You don't have to do anything with the driveshafts at 5", I don't know if the extra 2" makes that much of a difference either. In the rear, the kit comes with degree shims to rotate your pinion upward to compensate for the lift, but thats about it, there are no spacers for the driveshafts with the 5" kit.
I think to have the extra 2", an adjustable front trackbar would be required too. The trackbar relocate bracket for the SJ kit is beefy, but it is designed for a 5" lift, not a 7". Also, it seems like most guys are running the exteme drop pitman arm with 7" of lift, so there is some more exspense to think about.
So far I love the kit! It rides great and provides ample room for 35" tires, maybe 37's. I'm sure with the extra 2" you could run 37's easily.
Good luck, but plan on a whole day for the install, there is some drilling involved and having a right angle drill came in real handy too FWIW.
Bill