1) If you are on RedHat 7.3, you don't have to do anything special at all; it just all works. Otherwise I don't know.
2) The core will install on PG 7.3, but not all packages will (and I don't know yet which ones)
3) Yes, the dotLRN head will install on the OACS head as far as I know. But neither is overly stable. I would go with dotLRN 1.0 and OACS 4.6 if you're doing anything serious with it.
4) As far as I know there's no problem with unrelated modules and dotLRN.
