If all else fails, you might run it by a locksmith shop (if you can get it moving) and let them give it a try, they might know a trick. I've never seen an ignition lock clylinder that could not be replaced. It's a pain, but not that difficult, a two hour job maybe. And a new lock cylinder can be rekeyed to your key, too. Any locksmith can do it, takes ten minutes. I've done many of these repairs, and I have a steering wheel puller, a horn ring compressor, and a tilt bushing puller (which I made myself designed around the Snap-on one), though you shouldn't need all that to replace a lock cylinder.
According to my ('97) FSM, which should be similar if not the same, you pull the airbag and the wheel. Then there's a hole in the shroud you can see with the wheel pulled, called the release access hole. You stick a screwdriver through that hole and push a release button, and the lock cylinder comes out. The new one just pushes in and snicks into place.
On the interlock cable, my FSM says it's right next to the shifter cable at the front of the shifter, so remove the shifter bezel and console. The interlock cable should be the one on the passenger side. There's a release button on the little clip that attaches it to the shifter bracket. You can push that button and release the cable, then manipulate it until you can turn the lock cylinder (if it's what's causing the problem). In my FSM the adjustment for it is covered in the AW4 transmission section, on the last page.