The scenario I initially described is exactly what I did with my Jeep. I used a crown automotive lock cylinder and had NOS AMC Jeep keys (j) copied from the aftermarket key. I get where you're coming from but I think you are overthinking it...
1985 Jeep Cherokee XJ 4 door automatic 2.8L 4x4
Picking up this weekend.... probably.
It's here.
Power locks set up for keyless remote, but manual windows.
1986 2.5L, 4 speed manual transmission, 4x4. 130,000 miles
Second-ish owner
Bought from Central Wisconsin and dragged to Southwest Chicago burbs.
Currently non-running. Will probably be a part-out but haven't decided 100%.