Everything you outlined seems do able.

I suspect you could find an engine/transmission cheaper then a whole wrecked car. The only benefit would be the PCM module, there is a company I can't think of right now that can flash them for standalone/transmission control. For me personally the NAG1 would be too much work and I would put a 518 in.

Front suspension, maybe an after market mustang II suspension? should be a company that makes one that fits into a truck. Use the biggest brakes that fit in the rims you want to run.

The rear if the truck had an 8 3/4 I would just put disks on that, if its something else maybe put an 8.8" ford under it, or a car style Dana 60. 4 link you will have to Fab your own but it shouldn't be too bad.