Im really hoping one of the DF guys can hop on and give me a yeah or nah.
The DF guys are very good to us, their customers. That said, this forum is mostly community-driven. You will get a faster answer if you call DF directly, in my opinion.
I may be uniquely qualified (ha!) in one way to give you some advice on this, though. I personally dismantled two donor cars, one LSJ and one LNF, so I've had the harnesses side by side. The ECM from the LSJ is a completely different design than the ECM from the LNF. The LSJ has two body harness connectors, and the LNF only has one body harness connector that is completely different than either on the LSJ. There are other minor differences (LNF cars have a yaw sensor while LSJ cars do not), but the differing ECM connector(s) would seal the deal for me.
If you really are set on using an LSJ harness with an LNF engine, there are subscription services available that can help you identify all the wires in each connector. I do not have any of those personally, so someone else may have to chime in at this point.
*edit* Added the bit about having had two donors.