You have a couple options with the 4L80E. Buy a stand-alone controller, or swap over all the electronics and wire harness. You'll have to do that for the EFI engine anyway, or convert it to MFI. If you intend to EVER convert to a mechanical fuel system, it will never be easier than during your conversion. That will eliminate most of the electronic stuff and harness swap. This changes the tranny control options a bit, but much easier if you use a stand-alone controller.

The fuel tank will be fine, if it's in good condition. You'll need to install the Diesel tank sender and return line, though.

There are lots of pics here, and other sites. Try a search. To relocate the turbo, you can fab your own plumbing, or use a Banks exhaust manifold/crossover system for that body series (82-91). They often go for cheap on Ebay, or a member here may have one laying around collecting dust.