Just to clear some things up:

Your targets for donors are 1992 trucks/RCs with 318 or 1993 trucks/RCs with 5.2 r 5.9, The years prior (1988-1991 for 5.2, 1989-1992 for 5.9) were TBI and those harnesses are quite difficult to transition to work on a magnum engine. If you want to keep the fuel injection, the fuel tank really should be acquired for that application- it will make things easier for you. Even the cab harness is different on 3 major wire locations comparing 1991-1992 for example. People used to use 1992-1995 dakota harnesses for this swap alot back in the day, but not as easy as full size harness. Summary- you need the engine, cab and chassis harness

Transmission options if overdrive is required range from 1990-1995. Most 5.2 a518/46RHs were lockup but (1992s were for sure in light duty trucks) but 5.9s are hit or miss til 1993 on lock up. 1994 -1995 will be lockup.

OBD 2 started in 1996 and things get more complicated after that from a wiring standpoint.

Axles can be anything from a 4x4 from 81-93 and for rear axle, from a 2wd from 1985 up. Beware of the 9 1/4 HD. Used on light duty 3/4 ton trucks and everyone calls it a dana 60- people dont bother to look, nor do they care when selling them

Cam and a 4 barrel will make a 5.9 magnum act like a 5.7 hemi. Best years for 5.9 magnum are 1999-2003. The camshaft was changed to the 1998 Grand cherokee 5.9 limited cam. There is no best years for 5.2, thought the 1992-1993 5.2 exhaust manifolds had the 2 1/8 outlets and are thought to flow better

doing a 5.9 magnum should be cheaperthan 5.7. I cannot get a 5.7 in Maine for less than 1900, while I can get a 5.9 for 700 with less than 100k if patient. But the 5.7 needs a special aftermarket ECM harness if going that way that is at least 1000 extra, plus oil pan, motor mounts, oil filter adapter. 5.7 has much more potential but at what cost?