Rear sway bar after leaf spring relocation??

Well, I think it would be safe to say it will complicate it. The one I have (Addco, 20 years old, axle-mounted) is not dependent on the spring location, in itself, but the narrower spring perches might get in the way (very likely, I think). You might be safer with a chassis-mount bar. I'm not sure who makes one, but you could try Firm Feel and Hellwig to start. If all else fails, Pegasus Racing has build-it-yourself bars with adjustable width and arm length.