for just a stock spec daily driver the stock pcm would probably be fine no reflashing needed. It is fairly simple to do the wiring. The motor mounts and tranny would be additional cost.
Exactly what this guy said. You'll spend some on the rest of the car for the V8 swap, but it'll be night and day adding a good amount of power.
That said- knowing how cheap 4x4 318/360s are here I think that'd be a good donor. If not that one, there'll probably be another. People assume 4x4 means rust and more issues so the far end of fair 4x4s often end up cheaper than 2wds here at least. The 4x4 trans wouldn't really be a problem- the trans and the t-case separately or together should pay for a 904 or 727 small block for the car. For the guy that doesn't want to cut his tunnel or run steep gears, a 4x4 donor is probably not a bad deal at all.
There's not really any way you're better off with the early '90s setup. OBD-II V6/V8 vans also had hydraulic transmissions at least up to '99. The flexplate balance means you can just grab the EFI flexplate and if you never use EFI, you have it balanced. If you use EFI later- all that needs added is the crank sensor.