Not to be redundant, but is the above mentioned ATF compatible with
the older Chryslers manufactured even before this new ATF came out?
Or are you better off using Dexron in the old cars which came with it?
Unless that would just be a waste of money (I don't know how much more
expensive the new stuff is).

86 Lebaron (3 spd auto)
90 and 89 Caravan (604's)

BTW is the above mentioned LeBaron supposed to have a lock-up converter?
I thought pretty much everything had one by that year (it's a 2.2).