We use the following for defender builds:
steering
axles and radius and trailing arms and rear wishbone
engine wiring loom and ecu
heads, injection system, y pipe, block depending on milage
trans and transfer case, shifters and linkage
front drive shaft (solid vs defender tube)
frame side engine mounts and rear tcase frame side mount brackets
Sell the carcass to scrapper to get it out of here -typically get $120-140, never pull glass, interior, anything .07 lb.
Have found there is next to zero demand for doors, seats, interior panels etc so have discarded 8 trucks less the list above in the past 12 mos. We only buy the 96-99 gems trucks for donors.
You said you wanted it for its vented front brakes and disc rears. Disco 1's didnt have vented front brakes. I put vented rotor/caliper setups on these axles all the time but wanted to give you a heads up they aren't there stock. If its local and cheap its hard to go wrong for less than 1k.