I think it'd be easier & less spendy to set up the Demon than the AMX. AMX I think still had kind of a wacky ft suspension, parts in general harder to find. Plus side, they're rare enough that they're unique.

The Penske/RWR TransAm Javelin we restored & ran in vintage events had fabricated spindles & such, looked like some Ford stuff in there as well; I'm sure they didn't do all that because they were bored...another thing if your AMX plan would include AMC power is they had oiling problems until they went to a dry-sump with a lot of scavenge & feed work. One of the guys in Vintage TA with an older Javelin that can't run a dry sump (wasn't legal for '68 cars) has had problems just like they did back in the day.